Ceramic anion exchange material

Abstract

To provide an anion-exchange membrane.SOLUTION: In one embodiment, an anion-exchange membrane including silica-base ceramic which forms coating on a porous support membrane and / or in the porous support membrane is described. The anion-exchange membrane and material can possess some structural or chemical attributes (such as pore size / distribution, chemical functionalization), which can, alone or in combination, create advantageous performance characteristics in some of various applications in which the selective transportation of positive charged ion through a membrane / material is desirable. In one embodiment, the silica-base ceramic includes relatively small pores (for example, nearly spherical nano-pores) which can contribute to some of such advantageous characteristics. In one embodiment, the anion-exchange membrane or material includes a quarternary ammonium group covalently bonded to the silica-base ceramic.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Related Applications This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 62 / 857,227, filed June 4, 2019, and entitled "CERAMIC ANION EXCHANGE MATERIALS," which is incorporated herein by reference in its entirety for all purposes.

[0002] Ion exchange membranes and materials, and related methods, are generally described. [Background technology]

[0003] Anion exchange membranes and materials are used in a variety of industrial applications where the selective transport of negatively charged ions is desirable. In the case of anion exchange membranes, negatively charged ions can be selectively transported across the membrane. One type of anion exchange membrane is a hydroxide ion exchange membrane, although anion exchange membranes capable of selectively transporting other types of negatively charged ions exist. Certain embodiments of the present disclosure relate to compositions, membranes, and materials according to the present invention, and related methods, for improving the performance and / or properties of anion exchange membranes and materials. Summary of the Invention [Means for solving the problem]

[0004] Anion exchange membranes and materials, including silica-based ceramics, and related methods are generally described. The inventive subject matter, in some cases, includes interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0005] In one aspect, an anion exchange membrane is provided. In one embodiment, the anion exchange membrane includes a porous support membrane and a silica-based ceramic coating at least a portion of the porous support membrane. The silica-based ceramic includes quaternary ammonium groups covalently bonded to the silica-based ceramic. The silica-based ceramic has an average pore size of 10 nm or less.

[0006] In one embodiment, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating formed on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The anion exchange membrane has a chloride ion conductivity of 0.00001 S / cm or greater.

[0007] In one embodiment, the anion exchange membrane comprises a silica-based ceramic, and the anion exchange membrane has a water absorption of 10% by weight or more and a linear expansion of 10% or less.

[0008] In one embodiment, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic forming a coating on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The quaternary ammonium groups are immediately adjacent to the surface of the porous support membrane.

[0009] In one embodiment, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating at least a portion of the porous support membrane, the silica-based ceramic comprising quaternary ammonium groups covalently bonded to the silica-based ceramic, and at least 50% of the pore volume of the porous support membrane is filled with the silica-based ceramic.

[0010] In one embodiment, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating formed on and / or within the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The anion exchange membrane has an anion exchange capacity of 0.01 meq / g or greater.

[0011] In one embodiment, the anion exchange membrane comprises a porous support membrane and a silica-based ceramic coating at least a portion of the porous support membrane. The silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. The quaternary ammonium groups are present in the anion exchange membrane in an amount of 0.01 mmol or more per gram of the anion exchange membrane.

[0012] In one embodiment, an anion exchange material is provided. The anion exchange material comprises a silica-based ceramic containing quaternary ammonium groups covalently bonded to the silica-based ceramic. The silica-based ceramic contains Si in an amount of 6% or more by weight of the silica-based ceramic. The anion exchange material has an anion exchange capacity of 0.01 meq / g or more. The silica-based ceramic has an average pore size of less than 10 nm.

[0013] In one embodiment, an anion exchange membrane is provided. In one embodiment, the anion exchange membrane comprises a silica-based ceramic containing Si in an amount of 6% or more by weight of the silica-based ceramic. The anion exchange membrane has an anion exchange capacity of 0.01 meq / g or more.

[0014] In one embodiment, the anion exchange membrane comprises a silica-based ceramic, and has an anion exchange capacity of 0.01 meq / g or more and a linear expansion of 10% or less.

[0015] In one embodiment, an anion exchange membrane is provided, the anion exchange membrane comprising a silica-based ceramic containing Si in an amount of 6% or more by weight of the silica-based ceramic, and the anion exchange membrane has an anion permselectivity of 65% or more.

[0016] In one embodiment, an anion exchange membrane is provided. The anion exchange membrane comprises a silica-based ceramic containing Si in an amount of 6% or more by weight of the silica-based ceramic. The anion exchange membrane has a chloride ion conductivity of 0.00001 S / cm or more.

[0017] In one embodiment, the anion exchange membrane is a silica-based ceramic and has a chloride ion conductivity of 0.00001 S / cm or more and a linear expansion of 10% or less.

[0018] In one embodiment, an anion exchange membrane is provided. The anion exchange membrane comprises a silica-based ceramic containing Si in an amount of 6% or more by weight of the silica-based ceramic. The anion exchange membrane has a solubility of 100 mL / (hr·bar·m 2 ) has the following permeability to water.

[0019] In certain embodiments, the anion exchange membrane comprises a silica-based ceramic containing Si in an amount equal to or greater than 6% by weight of the silica-based ceramic.

[0020] In one embodiment, the anion exchange membrane comprises a silica-based ceramic containing Si in an amount equal to or greater than 6% by weight of the silica-based ceramic. When the anion exchange membrane is in a dry state, the pores of the silica-based ceramic fit a model of a small-angle scattering spectrum having intensity (I) as a function of scattering vector, q, as follows:

number

number

[0021] In one embodiment, a method for forming an anion exchange membrane is described. In one embodiment, the method includes exposing a porous support membrane, at least a portion of which is coated with a silica-based ceramic, to an amine, where the silica-based ceramic includes a moiety containing a leaving group covalently bonded to the silica-based ceramic. The silica-based ceramic includes Si in an amount equal to or greater than 6% by weight of the silica-based ceramic. The method includes reacting the amine with the moiety to release the leaving group and form a quaternary ammonium group covalently bonded to the silica-based ceramic.

[0022] In one embodiment, a method for forming an anion exchange material is described. In one embodiment, the method includes exposing a resin containing a silica-based ceramic to an amine. The silica-based ceramic includes a moiety containing a leaving group covalently bonded to the silica-based ceramic. The silica-based ceramic includes Si in an amount equal to or greater than 6% by weight of the silica-based ceramic. The method includes reacting an amine with the moiety to release the leaving group and form a quaternary ammonium group covalently bonded to the silica-based ceramic.

[0023] In certain embodiments, a method is provided for using the anion exchange membrane described herein in an electrochemical application. The method includes contacting the anion exchange membrane with an electrolyte. The method includes passing an electric current through electrodes in electrical communication with the electrolyte.

[0024] In certain embodiments, a method is provided for using the anion exchange material described herein in an electrochemical application. The method includes contacting the anion exchange material with an electrolyte. The method includes passing an electric current through electrodes in electrical communication with the electrolyte.

[0025] In some embodiments, a method is provided for using the anion exchange membrane described herein as an adsorbent material. In some embodiments, the method includes flowing a fluid through the anion exchange membrane. The method includes adsorbing a component of the fluid.

[0026] In certain embodiments, a method is provided for using the anion exchange material described herein as an adsorbent material. The method includes flowing a fluid through the anion exchange material. The method includes adsorbing a component of the fluid.

[0027] In certain embodiments, a method is provided for using the anion exchange membranes described herein in separation applications, the method comprising applying a transmembrane pressure to the anion exchange membrane.

[0028] Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying figures. In cases where the specification and any document incorporated by reference includes conflicting and / or inconsistent disclosure, the specification shall control.

[0029] Non-limiting embodiments of the present invention are described by way of example with reference to the accompanying drawings, which are schematic and are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown is typically represented by a single numeral. For clarity, not every component is labeled in every drawing, and not every component of each embodiment of the present invention is shown unless illustration is necessary to enable those skilled in the art to understand the invention. [Brief explanation of the drawings]

[0030] [Figure 1A] 1 is a schematic cross-sectional view of an exemplary anion exchange membrane comprising a silica-based ceramic according to an embodiment. [Figure 1B] FIG. 1 is a schematic cross-sectional view of an exemplary anion-exchange membrane comprising a silica-based ceramic according to an embodiment, with an inset showing a close-up of the pores of the silica-based ceramic. [Figure 2A] FIG. 1 is a schematic top-down view of an exemplary anion exchange membrane comprising a silica-based ceramic and a porous support membrane, according to an embodiment. [Figure 2B] 1 is a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane element, according to an embodiment. [Figure 3] FIG. 1 is a schematic diagram of quaternary ammonium groups covalently bonded to a silica-based ceramic according to some embodiments. [Figure 4A] FIG. 1 is a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane element, according to an embodiment, wherein the coating comprises quaternary ammonium groups substantially uniformly distributed within the silica-based ceramic across the thickness of the coating. [Figure 4B] FIG. 1 is a schematic cross-sectional view of an exemplary silica-based ceramic coating on a portion of a porous support membrane element, according to an embodiment, wherein the coating comprises quaternary ammonium groups that are not substantially uniformly distributed within the silica-based ceramic across the thickness of the coating. [Figure 5]FIG. 1 is a schematic top-down view of an exemplary anion exchange membrane comprising a silica-based ceramic and a compressible edging material, according to an embodiment. [Figure 6] 1 is a flow chart illustrating steps of an exemplary procedure for making a ceramic anion exchange membrane, according to an embodiment. [Figure 7] 1 is a schematic cross-sectional view of an anion exchange material comprising a silica-based ceramic according to an embodiment, wherein the anion exchange material comprises quaternary ammonium groups covalently bonded to the silica-based ceramic. [Figures 8A-8D] 1 shows anion permselectivity, water permeability, chloride ion conductivity, and small angle X-ray scattering data and fitting results for an exemplary anion exchange membrane, according to certain embodiments. [Figure 9A] 1 shows small angle X-ray scattering data and fitting results for an exemplary anion exchange membrane, according to certain embodiments. [Figure 9B-9D] 1 shows pore radius, volume porosity, and anion exchange capacity data for exemplary anion exchange membranes as a function of TEOS:TMAPS molar ratio, according to certain embodiments. [Figures 10A-10B] 1 shows permselectivity and chloride ion conductivity data for exemplary anion exchange membranes at different porous support membrane thicknesses, according to certain embodiments. [Figures 11A-11B] 1 shows permselectivity and chloride ion conductivity data for exemplary anion exchange membranes as a function of number of coatings, time exposed to silicon-containing precursor sol, and drying conditions, according to certain embodiments. [Figure 11C] 1 shows a cross-sectional SEM image of an exemplary anion exchange membrane, according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] Anion exchange membranes and materials, including silica-based ceramics, and related methods are provided. In certain aspects, anion exchange membranes including silica-based ceramics that form a coating on and / or within a porous support membrane are described. The anion exchange membranes and materials can have several structural or chemical attributes (e.g., pore size / distribution, chemical functionalization) that, alone or in combination, can provide advantageous performance characteristics in any of a variety of applications in which selective transport of negatively charged ions through the membrane / material is desirable. For example, the anion exchange membranes or materials described herein can exhibit relatively high anion exchange capacity, anion permselectivity, and / or mechanical burst strength, while in some cases also experiencing relatively low dimensional swelling (e.g., upon contact with water). In certain embodiments, the silica-based ceramics contain relatively small pores (e.g., roughly spherical nanopores) that can contribute to some of these advantageous properties.

[0032] In certain embodiments, the anion exchange membrane or material comprises quaternary ammonium groups covalently bonded to a silica-based ceramic. In some such cases, the quaternary ammonium groups are present at a relatively high loading compared to certain existing anion exchange materials. In certain embodiments, the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating formed by the silica-based ceramic, which may, in some cases, provide an advantage over certain existing membranes that may be functionalized only at or near the surface.

[0033] In certain embodiments, the anion exchange membranes and materials described herein can be made by sol-gel techniques, such as by co-condensation of certain silanes in a porous support membrane. The anion exchange membranes and materials can be useful in several applications, such as electrochemical (e.g., redox flow batteries) and purification (e.g., desalination, gas-liquid separation) processes.

[0034] Certain commercially available anion exchange membranes are made from hydrocarbon- or perfluorocarbon-based polymers containing covalently bonded quaternary ammonium moieties. As a result, these anion exchange membranes have a nanostructure characterized by a mixture of interconnected, string-like hydrophilic domains in a hydrophobic matrix. In the presence of water (e.g., when certain existing anion exchange membranes are used), these hydrophilic domains tend to swell (e.g., undergo dimensional swelling, such as linear expansion). Swelling of anion exchange membranes can be problematic in certain applications because it can cause tension that can lead to membrane tearing and device failure. While certain techniques, such as chemical cross-linking and / or mechanical reinforcement of the membrane, can sometimes reduce swelling, improved compositions and structures are needed that can more effectively reduce swelling while maintaining or even enhancing the performance of anion exchange membranes and materials.

[0035] It has been observed that anion-exchange membranes comprising rigid structures, such as ceramics, can experience less swelling than hydrocarbon- or perfluorocarbon-based membranes. However, certain existing ceramics are believed to be too brittle to be used in freestanding ceramic-based membranes. Thus, previous attempts to incorporate ceramics into anion-exchange membranes have typically involved the incorporation of ceramic nanoparticles, for example, into a polymer matrix. In connection with the present disclosure, it has been unexpectedly observed that anion-exchange membranes and materials comprising silica-based ceramics can be realized without the need for nanoparticles incorporated into a polymer matrix. For example, it has been observed that anion-exchange membranes containing silica-based ceramics comprising functional groups, such as quaternary ammonium groups, covalently bonded to the silica-based ceramic are possible. In certain embodiments, such functionalized silica-based ceramic compositions can have an ordered nanoporous structure. In certain embodiments, the resulting anion-exchange membranes exhibit unexpectedly beneficial performance characteristics (e.g., relatively high anion exchange capacity, relatively high chloride ion conductivity, relatively high permselectivity, high mechanical burst strength) while exhibiting relatively low dimensional swelling. Such anion-exchange membranes and materials, and methods for making and using them, are described herein.

[0036] In one aspect, anion exchange membranes are generally described. FIG. 1A is a schematic cross-sectional view of an exemplary anion exchange membrane 100. In certain embodiments, the anion exchange membrane can achieve any of the various advantageous properties and performance characteristics reported in this disclosure. For example, the anion exchange membrane 100 can exhibit a relatively high anion exchange capacity, a relatively high anion permselectivity, a relatively high chloride ion conductivity, a relatively low osmotic water permeability, and / or a relatively low dimensional swelling (e.g., a relatively low linear expansion), the details of which are provided in more detail below. As described above, the anion exchange membrane can be suitable for use in any of a variety of applications described in more detail below.

[0037] Referring again to FIG. 1A, the exemplary anion-exchange membrane 100 includes a silica-based ceramic 150. In certain embodiments, a silica-based ceramic is a ceramic that includes or is formed from a network of silica (SiO), although the silica-based ceramic may include groups (e.g., terminal moieties) not encompassed by the SiO formula. In certain embodiments, the silica-based ceramic is porous (e.g., nanoporous). FIG. 1B is a schematic cross-sectional view of an exemplary anion-exchange membrane 100 including an exemplary porous (e.g., nanoporous) silica-based ceramic 150, according to certain embodiments. FIG. 1B shows an inset illustrating a magnified view of the silica-based ceramic 150 showing exemplary pores, including exemplary pore 152. The porosity (e.g., nanoporosity) of the silica-based ceramic can contribute, at least in part, to the performance characteristics of the anion-exchange membrane. Silica-based ceramics are described in more detail below. It should be understood that the figures depicted herein are for illustrative purposes and may not necessarily be drawn to scale.

[0038] In some embodiments, the anion exchange membrane includes a porous support membrane. For example, in some embodiments, the anion exchange membrane 100 includes a porous support membrane. The porous support membrane can provide mechanical support for the entire anion exchange membrane. FIG. 2A shows a schematic top-down view of an exemplary anion exchange membrane 100 including a silica-based ceramic 150 and a porous support membrane 130 obscured by the silica-based ceramic 150, according to some embodiments. For illustrative purposes, FIG. 2A shows the porous support membrane 130 without the silica-based ceramic 150 present to the left of the arrow, while the anion exchange membrane 100 to the right of the arrow includes the silica-based ceramic 150 present, thereby obscuring the porous support membrane. It should be understood that FIG. 2A is illustrative of non-limiting embodiments, and in some embodiments, the coating formed by the silica-based ceramic does not completely cover the porous support membrane. For example, in some such embodiments, portions of the porous support membrane 130 may not be obscured by the silica-based ceramic 150.

[0039] In some embodiments, the anion exchange membrane includes a silica-based ceramic coating at least a portion of the porous support membrane. Referring again to FIG. 2A , the anion exchange membrane 100 includes a silica-based ceramic 150 coating the porous support membrane 130 (hidden from the view in the anion exchange membrane 100 to the right of the arrow). In some such embodiments, the silica-based ceramic forms a coating on and / or within the porous support membrane. For example, the porous support membrane may be impregnated or encapsulated in the silica-based ceramic. In some embodiments, the silica-based ceramic coats a portion, but not all, of the porous support membrane. In such embodiments, the porous support membrane may be substantially coated with the silica-based ceramic.

[0040] 2B shows a schematic cross-sectional view of an exemplary coating 140 formed by a silica-based ceramic 150, according to certain embodiments. As exemplarily shown in this figure, the coating 140 of silica-based ceramic 150 is on the surface of a porous support membrane component 135 (e.g., a single fiber on or within a porous support membrane), according to certain embodiments, the cross-section of which is shown in FIG. 2B. This exemplary embodiment (e.g., a coated fiber) can be part of an anion-exchange membrane in which the silica-based ceramic completely coats the porous support membrane or partially coats the porous support membrane.

[0041] When a part (e.g., a layer, a coating) is said to be "on," "adjacent," "in contact with," or "supported by" another part, it should be understood that it can be directly on that part, or that intervening parts (e.g., layers, coatings) may also be present. A part "directly on," "directly adjacent," "in direct contact with," or "directly supported by" another part means that there are no intervening parts. When a part is said to be "on," "adjacent," "in contact with," or "supported by" another part, it should also be understood that this can include the entire part or a portion of a part.

[0042] In some embodiments, a silica-based ceramic coating (e.g., coating 140) is present on (e.g., directly on) the surface of the porous support membrane. In some embodiments, the coating is present on the surface of the porous support membrane, while the interior of the porous support membrane is substantially uncoated. However, in other embodiments, the silica-based ceramic coating is present within at least a portion of the interior of the porous support membrane (i.e., throughout the thickness of the porous support membrane). As an example, the silica-based ceramic coating is formed on components of the interior of the porous support membrane that are accessible, for example, through pores or voids. In some such cases, the coating fills at least some or all of the pores of the porous support membrane. In some embodiments, at least a portion of the interior of the porous support membrane is coated, while the surface of the porous support membrane is substantially uncoated.

[0043] As described in more detail below, the porous support membrane may include a support component, such as fibers, that provide structural support to the membrane. In some embodiments, substantially all of the support component of the porous support membrane is coated with the silica-based ceramic. As an example, in some embodiments, the porous support membrane includes a nonwoven fabric of fibers. In some such cases, substantially all of the fibers, including the fibers within the porous support membrane, are coated with the silica-based ceramic. However, in other embodiments, not all of the support component of the porous support membrane is coated with the silica-based ceramic. For example, in some embodiments where the porous support membrane includes fibers as support components, not all of the fibers are coated with the silica-based ceramic. The extent of coating can vary. In some cases, the silica-based ceramic coating covers the entire porous support membrane (e.g., as shown for anion-exchange membrane 100 to the right of the arrow in FIG. 2A ), while in other cases, the silica-based ceramic coating covers only a portion of the porous support membrane (e.g., only a subset of the area of ​​the porous support membrane is coated, or only a portion of the support component is coated).

[0044] In some embodiments in which the silica-based ceramic forms a coating on and / or within the porous support membrane, the silica-based ceramic fills substantially all of the pores of the porous support membrane. For example, referring again to FIG. 2A , in some embodiments, when the silica-based ceramic coats the porous support membrane 130, all of the pores of the porous support membrane 130, including pore 132, are completely filled with the silica-based ceramic. In such embodiments, the porosity of the resulting overall anion-exchange membrane will correspond to the porosity of the silica-based ceramic material. In other embodiments in which the silica-based ceramic forms a coating on and / or within the porous support membrane, the silica-based ceramic does not completely fill the pores of the porous support membrane, but reduces the pore size (e.g., average pore size) of the porous support membrane. In such embodiments, the overall porosity of the resulting overall anion-exchange membrane will differ from the porosity of the silica-based ceramic material itself. The resulting total anion-exchange membrane in this case has a porosity different from that of the silica-based ceramic coating due to the presence of both reduced-size pores in the porous support membrane and pores corresponding to the silica-based ceramic. In such embodiments, the silica-based ceramic coating can have a porosity in one or more of the ranges described herein, and the total anion-exchange membrane can have a porosity in one or more of the ranges described herein.

[0045] In some, but not necessarily all, embodiments, the anion exchange membrane comprises one or more additional layers or coatings on the coating comprising the silica-based ceramic (e.g., on top of the silica-based ceramic coating). However, in some embodiments, no other layers or coatings are present on the coating comprising the silica-based ceramic (e.g., the silica-based coating forms the outermost surface of the anion exchange membrane). In some embodiments, the silica-based ceramic forms a single layer on the porous support membrane.

[0046] Formation of a coating on and / or within at least a portion of a silica-based ceramic porous support membrane can be carried out using any of a variety of suitable techniques. In some embodiments, the silica-based ceramic coating (e.g., coating 140) is formed using a sol-gel technique. For example, referring again to FIG. 2A , in some embodiments, the porous support membrane 130 (shown to the left of the arrow) is coated using a sol-gel technique, thereby resulting in an anion-exchange membrane 100 comprising a silica-based ceramic 150 coated on and / or within at least a portion of the porous support membrane 130 (shown to the right of the arrow). In some such cases, sol-gel techniques such as those described herein can provide relatively rapid and low-cost formation of anion-exchange membranes comprising silica-based ceramic. In some such cases, relatively mild conditions can be used to form a silica-based ceramic coating using a sol-gel technique, and the resulting silica-based ceramic can have particular structural characteristics (e.g., ordered nanopores) that can provide advantageous performance in some cases. Exemplary sol-gel techniques are described in more detail below.

[0047] In some embodiments, the silica-based ceramic includes one or more functional groups covalently bonded to the silica-based ceramic. The presence of functional groups covalently bonded to the silica-based ceramic may contribute, at least in part, to the performance of the anion exchange membrane. For example, in some embodiments, the silica-based ceramic includes functional groups capable of binding and dissociating anions. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are positively charged functional groups. For example, in some embodiments, the functional groups covalently bonded to the silica-based ceramic are quaternary ammonium groups. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are imidazole groups. In some embodiments, the functional groups covalently bonded to the silica-based ceramic are weak base groups such as amine groups (e.g., tertiary amine groups). The functional groups may be bonded to Si in the silica-based ceramic via linking groups (e.g., organic linking groups). For example, the nitrogen of the quaternary ammonium group may be optionally substituted C 1~18 Alkylene and arylene (or C1~8 Alkylene and arylene, or C 1~4 The quaternary ammonium group may be covalently bonded to Si in the silica-based ceramic via an organic linker, such as a linker selected from the group consisting of alkylene and arylene. It should be understood that in this disclosure, any description of an item "selected from" a list of items may be replaced with a description of an item selected from the group consisting of those items. For example, in some embodiments, the nitrogen of the quaternary ammonium group may be replaced with an optionally substituted C 1~18 It can be covalently bonded to the Si in the silica-based ceramic via an organic linker, such as a linker selected from the group consisting of alkylene and arylene.

[0048] The functional groups may be capable of binding and dissociating cations, such as protons or certain metal ions. For example, quaternary ammonium groups attached to silica-based ceramics may be capable of binding and dissociating anions, such as hydroxides or halides. Exemplary anions that may be capable of binding and dissociating with functional groups (e.g., quaternary ammonium groups) include F - , Cl - , Br - , I - , O.H. - , SO3 - , CO3 - , PO4 3- , BO3 - , NO3 - , NO2 - , and ClO3 - Examples include:

[0049] FIG. 3 is a schematic diagram of quaternary ammonium groups covalently bonded to a silica-based ceramic 150, according to certain embodiments. As exemplarily shown in this figure, the quaternary ammonium groups are covalently bonded to the interior of the silica-based ceramic material. In certain embodiments, the functional groups (e.g., quaternary ammonium groups) are exposed at the exterior surface of the silica-based ceramic (e.g., the exterior of a coating on the silica-based ceramic). In some cases, the functional groups covalently bonded to the silica-based ceramic groups (e.g., quaternary ammonium groups) are exposed at the surfaces of the pores of the silica-based ceramic. For example, in FIG. 3, the quaternary ammonium groups covalently bonded to the silica-based ceramic 150 are shown exposed at the surfaces of the pores 152 of the silica-based ceramic. Having functional groups, such as quaternary ammonium groups, present on the surfaces of the pores of the silica-based ceramic can, in certain embodiments, enable relatively efficient transport of anions through the anion-exchange membrane and / or a relatively high anion exchange capacity for the anion-exchange membrane.

[0050] Those skilled in the art will understand that the relative amount of conjugate acid of a functional group covalently bonded to a silica-based ceramic compared to the amount of conjugate base of the functional group present at any given time will depend on the conditions and environment of the anion exchange membrane or material. For example, in embodiments where the functional group is an imidazole or amine (e.g., a tertiary amine), the relative number of imidazolium to imidazole or ammonium to amine groups will depend, at least in part, on the pH of any solution with which the membrane or material is in contact, the pK of other functional groups, if any, and the like. a , and / or the concentration of anions in any solution with which the membrane or material is in contact.

[0051] In some embodiments, the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, the quaternary ammonium groups being substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating. The thickness of the coating refers to the thickness in a direction from the surface of the porous support membrane component covered by the coating (e.g., the surface of a single fiber of the porous support membrane) to the nearest exposed surface of the silica-based ceramic coating. The exposed surface of the silica-based ceramic coating refers to the exterior of the anion-exchange membrane, another layer or region of material, or any surface of the silica-based ceramic that is aligned with the unfilled pores or voids of the porous support membrane. For example, in one embodiment, the exposed surface may be exposed to air or another environment different from the silica-based ceramic coating itself. Figure 4A is a schematic cross-sectional view of an exemplary coating 140 of silica-based ceramic 150 on a portion of a porous support membrane component 135 (e.g., on or within a fiber of a porous support membrane), according to some embodiments. In some embodiments, the coating 140 in Figure 4A comprises quaternary ammonium groups that are substantially uniformly distributed within the silica-based ceramic 150 throughout the thickness 160 of the coating 140. Having functional groups, such as quaternary ammonium groups, substantially uniformly distributed within the silica-based ceramic throughout the coating thickness can, in some cases, provide a number of advantages. One advantage is that a substantially uniform distribution of functional groups within the silica-based ceramic can enable a relatively high loading of functional groups for a given amount of silica-based ceramic, which can lead to a high anion exchange capacity per unit mass and beneficial performance characteristics. Another possible advantage is that a substantially uniform distribution of functional groups within the silica-based ceramic can result in regions of the membrane having a relatively low amount of functional groups, resulting in a relatively small distance between functional groups within the membrane, in contrast to certain existing membranes in which the functional groups (e.g., quaternary ammonium groups) are relatively localized (e.g., near the surface), which can limit anion conductivity. A substantially uniform distribution of functional groups (e.g., quaternary ammonium groups) can be achieved, for example, using certain sol-gel techniques, as described in more detail below.

[0052] 4B is a schematic cross-sectional view of an exemplary coating 240 including a silica-based ceramic 250 on a portion of a porous support membrane element 135 (e.g., fibers on or within the porous support membrane), according to one embodiment. In FIG. 4B, the coating 240 includes sulfonic acid groups that are not substantially uniformly distributed within the silica-based ceramic 250 across a thickness 260 of the coating 240. Rather, in FIG. 4B, the quaternary ammonium groups are localized at or near the surface of the coating 240, rendering regions 245 of the coating free of quaternary ammonium groups.

[0053] Such a distribution of quaternary ammonium groups that is not substantially uniformly distributed can be obtained from a coating technique that uses surface functionalization, rather than the specific sol-gel technique described herein. For example, a coating comprising a silica-based ceramic containing quaternary ammonium groups that is not substantially uniformly distributed can be obtained from a fabrication technique in which a support (e.g., a porous support membrane) is first coated with a material (e.g., a ceramic, such as a silica-based ceramic) that does not contain quaternary ammonium groups (or contains a relatively low amount of quaternary ammonium groups). After the first coating step, a second coating step is then performed in which a material containing quaternary ammonium groups (or containing a relatively high amount of quaternary ammonium groups) is coated onto the first coating. Having a silica-based ceramic coating that does not have a substantially uniform distribution of quaternary ammonium groups can result in relatively poor performance of the resulting anion exchange membrane. For example, in certain embodiments, the anion exchange membrane can have a relatively low loading of quaternary ammonium groups compared to an anion exchange membrane having a coating with a substantially uniform distribution of quaternary ammonium groups. Furthermore, in some cases, such coatings may not have a substantially uniform distribution of quaternary ammonium groups, and thus regions having a relatively low abundance of quaternary ammonium groups (e.g., region 245) may have a relatively low anionic conductivity due to such regions.

[0054] In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating, the amount of quaternary ammonium groups does not vary by more than 50% at any given point within a cross-section of the coating thickness compared to the average amount of quaternary ammonium groups in the silica-based ceramic. For example, referring again to FIG. 4A , the amount of quaternary ammonium groups at any point A or any point B of cross-section 143 of coating 140 does not vary by more than 50% compared to the average amount of quaternary ammonium groups in coating 140. In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is within a range of 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 90% or more, 95% or more, or 99% or more of the average amount of quaternary ammonium groups in the coating. In some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is within a range of 100% or less, 99% or less, 95% or less, 90% or less, 75% or less, 70% or less, 60% or less, or less of the average amount of quaternary ammonium groups within the coating. Combinations of these ranges are possible. For example, in some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is within a range of 50% or more and 100% or less of the total average amount of quaternary ammonium groups within the coating.As an exemplary calculation, if a silica-based ceramic is measured to have a typical amount of quaternary ammonium groups of 5 weight percent (wt %) (as measured by scanning electron microscopy / energy dispersive X-ray technique (SEM / EDX)), and all points within at least five cross sections through the thickness of the silica-based ceramic (e.g., point A in FIG. 4A ) are measured to have an amount of quaternary ammonium groups greater than or equal to 2.5 wt % and less than or equal to 7.5 wt %, the silica-based ceramic would be considered to have quaternary ammonium groups substantially uniformly distributed throughout the coating thickness, based on the average amount of quaternary ammonium groups measured.

[0055] In contrast, in some cases where the quaternary ammonium groups are not substantially uniformly distributed within the silica-based ceramic across the thickness of the coating, the amount of quaternary ammonium groups is within less than 50% of the average amount of quaternary ammonium groups in the coating (in other words, the amount of quaternary ammonium groups varies by more than 50% at any given point within a cross-section of the thickness of the coating compared to the average total amount of quaternary ammonium groups in the silica-based ceramic). For example, referring again to FIG. 4B , the amount of quaternary ammonium groups at any point C or any point D of cross-section 243 of coating 240 varies by more than 50% compared to the average amount of quaternary ammonium groups in coating 240. As an exemplary calculation, if a silica-based ceramic is measured to have a standard amount of 5 wt. % quaternary ammonium groups, and any point in a cross-section through the thickness of the silica-based ceramic (e.g., point D in Figure 4B) is measured to have an amount of quaternary ammonium groups less than 2.5 wt. % or more than 7.5 wt. %, the silica-based ceramic would not be considered to have quaternary ammonium groups substantially uniformly distributed through the coating thickness, based on the average amount of quaternary ammonium groups measured.

[0056] In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating, the amount of quaternary ammonium groups does not vary by more than 75% at any given point within a cross-section of the coating thickness compared to the maximum amount of quaternary ammonium groups in the silica-based ceramic. For example, referring again to FIG. 4A , the amount of quaternary ammonium groups at any point A or any point B of cross-section 143 of coating 140 does not vary by more than 75% compared to the maximum amount of quaternary ammonium groups in coating 140. In some embodiments in which the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is 25% or more, 40% or more, 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 90% or more, 95% or more, or 99% or more of the maximum amount of quaternary ammonium groups in the coating. In some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is less than or equal to 100%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 75%, less than or equal to 70%, less than or equal to 60%, or less than or equal to the maximum amount of quaternary ammonium groups within the coating. Combinations of these ranges are possible. For example, in some embodiments, the amount of quaternary ammonium groups is distributed within the silica-based ceramic such that any given point within a cross-section of the coating thickness is greater than or equal to 25% and less than or equal to 100% of the total maximum amount of quaternary ammonium groups within the coating. As an exemplary calculation, if a silica-based ceramic is measured to have a maximum amount of quaternary ammonium groups of 10 wt. % (as measured by scanning electron microscopy / energy dispersive X-ray techniques (SEM / EDX)), and all points within at least five cross sections across the thickness of the silica-based ceramic (e.g., point A in FIG. 4A ) are measured to have an amount of quaternary ammonium groups of 2.5 wt. % or greater, the silica-based ceramic would be considered to have quaternary ammonium groups substantially uniformly distributed across the thickness of the coating, based on the maximum amount of quaternary ammonium groups measured.It should be understood that it is the relative amount of quaternary ammonium groups that is important in the above calculations, and the units used to express the amounts as determined from SEM / EDX techniques are not particularly important. Although weight percent is used in the above exemplary calculations, other units for expressing the amount of sulfonic acid and sulfonate groups are readily obtained from SEM / EDX techniques or can be derived from weight percentages as well.

[0057] In contrast, the quaternary ammonium groups are not substantially uniformly distributed within the silica-based ceramic throughout the thickness of the coating; in some cases, the amount of quaternary ammonium groups at a point is less than 25% of the maximum amount of quaternary ammonium groups in the coating (in other words, the amount of quaternary ammonium groups varies by more than 75% at any given point within a cross-section of the thickness of the coating compared to the maximum total amount of quaternary ammonium groups in the silica-based ceramic). For example, referring again to FIG. 4B , the amount of quaternary ammonium groups at any point C or any point D of cross-section 243 of coating 240 varies by more than 75% compared to the maximum amount of quaternary ammonium groups in coating 240. As an exemplary calculation, if a silica-based ceramic is measured to have a maximum amount of quaternary ammonium groups of 10 wt. %, and any point in a cross-section through the thickness of the silica-based ceramic (e.g., point D in Figure 4B) is measured to have an amount of quaternary ammonium groups of less than 2.5 wt. %, the silica-based ceramic would not be considered to have quaternary ammonium groups substantially uniformly distributed through the thickness of the coating, based on the maximum amount of quaternary ammonium groups measured.

[0058] The amount of quaternary ammonium groups within a coating and within any cross-section of the coating can be determined using a combination of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. For example, the following procedure can be performed: The anion exchange membrane is dried and a cross-sectional sample is mounted on an SEM stub. The sample is first imaged using secondary electron and / or backscatter detection, and then imaged by EDX. The EDX data can be acquired as a linear profile across the cross-sectional sample or as a map of the entire sample. The EDX data can then be interpreted to determine the average or maximum amount (e.g., in weight percent) of quaternary ammonium groups present in the coating, as well as the amount of quaternary ammonium groups at any point along the cross-section, using the linear profile from the SEM / EDX data. Three or more linear profiles can be acquired to determine a statistically representative set of data.

[0059] In some embodiments, the quaternary ammonium groups are directly adjacent to the surface of the porous support membrane. For example, referring again to FIG. 4A , according to some embodiments, coating 140 including silica-based ceramic 150 includes quaternary ammonium groups, and the quaternary ammonium groups are directly adjacent to porous support membrane component 135, thereby making it directly adjacent to the porous support membrane to which porous support membrane component 135 belongs. In some embodiments, there is no intervening layer between the silica-based ceramics including quaternary ammonium groups in the porous support membrane. For example, in some embodiments, there is no intervening layer between silica-based ceramic 150 and porous support membrane component 135 in FIG. 4A .

[0060] In some embodiments, the quaternary ammonium groups are relatively close to the surface of the porous support membrane (e.g., the surface of the support component that makes up the porous support membrane). For example, in some embodiments, at least a portion of the quaternary ammonium groups are within 1 μm, 500 nm, 100 nm, 50 nm, 10 nm, 5 nm, 1 nm, or less of the surface of the porous support membrane. In some embodiments, at least a portion of the quaternary ammonium groups are within 1 to 10 μm of the surface of the porous support membrane. In some embodiments, the quaternary ammonium groups are in contact (e.g., direct contact) with the surface of the porous support membrane. The distance between the porous support membrane and the quaternary ammonium groups can be determined, for example, using an analytical electron microscope equipped with a transmission electron microscope (TEM) and an X-ray spectrometer.

[0061] As described above, in certain embodiments, the anion exchange membrane or material has a relatively high loading of functional groups. For example, in certain embodiments, the anion exchange membrane or material has a relatively high loading of quaternary ammonium groups. Having a relatively high loading of functional groups, such as quaternary ammonium groups, can lead, at least in part, to beneficial performance characteristics of the anion exchange membrane or material. For example, a high loading of quaternary ammonium groups can contribute to relatively high anion exchange capacity, anion permselectivity, and / or anion conductivity (e.g., chloride ion conductivity, hydroxide conductivity). Certain methods described herein, such as certain sol-gel techniques involving co-condensation of functionalized and non-functionalized silanes, can provide loadings of quaternary ammonium groups that are otherwise difficult to achieve using certain existing techniques.

[0062] In some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or material in an amount of at least 0.01 mmol, at least 0.05 mmol, at least 0.1 mmol, at least 0.3 mmol, at least 0.5 mmol, at least 0.7 mmol, at least 1 mmol, at least 2 mmol, at least 3 mmol, or more per gram of anion exchange membrane or material. In some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or material in an amount of at most 10 mmol, at most 5 mmol, or less per gram of anion exchange membrane or material. Combinations of these ranges are possible. For example, in some embodiments, the quaternary ammonium groups are present in the anion exchange membrane or material in an amount of at least 0.01 mmol and at most 10 mmol, or at least 0.1 mmol and at most 10 mmol, per gram of anion exchange membrane or material. It should be understood that the loading described herein refers to the total amount of quaternary ammonium cations (i.e., charged groups) and quaternary ammonium salts (i.e., neutral groups containing quaternary ammonium groups associated with anions). For example, if an anion exchange membrane or material contained 0.1 mmol of free quaternary ammonium cations and 0.3 mmol of quaternary ammonium groups associated with anions per gram of anion exchange membrane or material, the quaternary ammonium groups would be present in the anion exchange membrane or material in an amount of 0.4 mmol per gram of anion exchange membrane or material. The loading of quaternary ammonium groups in an anion exchange membrane or material can be determined by measuring the anion exchange capacity of the anion exchange membrane, as described below, and equating the number of chloride ions measured in solution (as determined by titration) with the number of quaternary ammonium groups in the anion exchange membrane. The loading can then be determined by taking the number of quaternary ammonium groups (in mmol) and dividing by the weight (in g) of the dried anion exchange membrane. It should be understood that the above amounts and measurements of quaternary ammonium group loading refer to accessible quaternary ammonium groups, and not to quaternary ammonium groups that are inaccessible to solvents and ions (e.g., quaternary ammonium groups trapped within enclosed pores that cannot be accessed by solvents or anions).

[0063] As described above, a silica-based ceramic (e.g., silica-based ceramic 150) can be a ceramic that includes a network of primarily silica (SiO), although the silica-based ceramic can include groups (e.g., terminal moieties) not represented by the formula of SiO. For example, in some embodiments, the silica-based ceramic includes a network of silica that includes terminal hydroxy groups, terminal organic groups, and / or terminal functional groups (e.g., quaternary ammonium groups). In some embodiments, a relatively high percentage of the Si atoms in the silica-based ceramic are in a tetrahedral environment and are bonded to either oxygen, hydroxy groups, or functional groups (e.g., quaternary ammonium groups). For example, in some embodiments, a relatively high percentage of the silica-based ceramic includes the following structure (I): [ka] where each R group can independently be a moiety containing a functional group such as hydroxy, -OSiR3, or a quaternary ammonium group. For example, in some cases, R can be a trialkylammonium alkanoic acid group such as N,N,N-trimethylammonium propane. As can be seen from this structure, the silica-based ceramic can contain an extended (though not necessarily single-crystalline) ceramic structure containing a functional group such as a quaternary ammonium group covalently bonded to the silica-based ceramic. For example, in some embodiments, the silica-based ceramic can have the following structure (II): [ka] where each R group can independently be a moiety containing a functional group such as a hydroxy, -OSiR3, or a quaternary ammonium group.

[0064] In one embodiment, the silica-based ceramic has the following structure (III): [ka] where each R group can independently be a moiety containing a functional group such as hydroxy, -OSiR, or a quaternary ammonium group, and R' can independently be an optionally substituted alkyl, cyclyl, or aryl.

[0065] The silica-based ceramic of the anion-exchange membrane can have one or more properties of ceramics known in the art. For example, the silica-based ceramic can be relatively brittle, have a relatively high density, have a relatively high hardness, and / or have a relatively high melting point. In some embodiments, the silica-based ceramic is polycrystalline. The silica-based ceramics described herein are in contrast to anion-exchange membranes that include particles (e.g., nanoparticles) of silica (e.g., functionalized silica nanoparticles) suspended in a non-silica-based matrix (e.g., a polymer matrix, such as a carbon-based polymer matrix).

[0066] In some embodiments, Si is present in a relatively high amount in the silica-based ceramic. Si can be present in a relatively high amount in the silica-based ceramic because the silica-based ceramic is primarily silica-based, without a relatively high percentage of other components, such as a polymer matrix. In some embodiments, the silica-based ceramic comprises 6 weight percent (wt%) or more, 10 wt% or more, 12 wt% or more, 15 wt% or more, 17 wt% or more, 20 wt% or more, 24 wt% or more, 30 wt% or more, 40 wt% or more, or more. In some embodiments, the silica-based ceramic comprises 60 wt% or less, 50 wt% or less, 47 wt% or less, 40 wt% or less, 30 wt% or less, 28 wt% or less, 26 wt% or less, 24 wt% or less, 22 wt% or less, 20 wt% or less, 17 wt% or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the silica-based ceramic comprises an amount of Si in the silica-based ceramic of ≧6 wt % and ≦60 wt %, or ≧11 wt % and ≦26 wt %.

[0067] In some embodiments, the silica-based ceramic comprises 1.5 mole percent (mol%) or more, 3 mol% or more, 5 mol% or more, 8 mol% or more, 10 mol% or more, 12 mol% or more, 15 mol% or more, 18 mol% or more, 20 mol% or more, or more. In some embodiments, the silica-based ceramic comprises 33.4 mol% or less, 30 mol% or less, 28 mol% or less, 26 mol% or less, 24 mol% or less, 22 mol% or less, 20 mol% or less, 18 mol% or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic comprises 1.5 mol% or more and 33.4 mol% or less, 8 mol% or more and 20 mol% or less, 2.8 mol% or more and 18 mol% or less, or 12 mol% or more and 18 mol% or less, of Si in the silica-based ceramic.

[0068] In some embodiments in which the silica-based ceramic contains nitrogen-containing functional groups, such as quaternary ammonium groups, the molar ratio of Si to nitrogen in the silica-based ceramic depends on the loading of the nitrogen-containing functional groups in the silica-based ceramic. In some embodiments, the silica-based ceramic has a molar ratio of silicon to nitrogen of 1:1 or greater, 1.5:1 or greater, 2:1 or greater, 3:1 or greater, 4:1 or greater, 5:1 or greater, 10:1 or greater, 25:1 or greater, or greater. In some embodiments, the silica-based ceramic has a molar ratio of silicon to nitrogen of 120:1 or less, 75:1 or less, 50:1 or less, 25:1 or less, 10:1 or less, 4:1 or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic has a molar ratio of silicon to nitrogen of 1:1 or greater and 120:1 or less, 1:1 or greater and 10:1 or less, or 1:1 or greater and 4:1 or less.

[0069] In some embodiments, the molar ratio of Si to carbon in the silica-based ceramic depends on the loading of carbon-containing groups in the silica-based ceramic, such as organic moieties (e.g., organic functional groups). In some embodiments, the silica-based ceramic has a molar ratio of silicon to carbon (Si:C) of 1:100 or more, 1:75 or more, 1:50 or more, 1:40 or more, 1:25 or more, 1:16 or more, 1:10 or more, 1:5 or more, 1:3 or more, 1:1 or more, or more. In some embodiments, the silica-based ceramic has a molar ratio of silicon to carbon of 3,000:1 or less, 2,000:1 or less, 1,000:1 or less, 500:1 or less, 200:1 or less, 100:1 or less, 75:1 or less, 50:1 or less, 25:1 or less, 10:1 or less, 2:1 or less, 1:1 or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic has a silicon to carbon molar ratio of 1:100 or greater and 3:00:1 or less, 1:100 or greater and 100:1 or less, 1:40 or greater and 10:1 or less, or 1:3 or greater and 2:1 or less.

[0070] The weight percentages and mole percentages and mole ratios of the silica-based ceramics described above can be determined by removing the silica-based ceramic from the remainder of the anion exchange membrane or material (e.g., porous support membrane, compressible edging material, etc.) and performing elemental analysis such as inductively coupled plasma mass spectrometry (ICP-MS) or nuclear magnetic resonance (NMR).

[0071] As described above, in some embodiments, sol-gel techniques can be used to form silica-based ceramics. Accordingly, in some cases, the silica-based ceramic is derived from a sol-gel. In some embodiments, the sol used in the sol-gel technique is a silicon-containing precursor sol (i.e., the silica-based ceramic is derived from a silicon-containing precursor sol). During the fabrication of an anion-exchange membrane, one or more components of the anion-exchange membrane, such as the porous support membrane described herein, can be coated with a silicon-containing precursor sol during at least one step of the fabrication process. The silicon-containing precursor sol can include any of a variety of suitable silicon-containing precursor components, such as colloidal silica particles, siloxanes, silicate esters, silanols, silanes, alkoxysilanes, tetraalkyl orthosilicates, halosilanes, or combinations thereof. In some such embodiments, the silica-based ceramic is derived from a silicon-containing precursor sol containing two or more different silicon-containing precursor components. In some such cases, the silica-based ceramic is formed by co-condensation of two or more silicon-containing precursor components (e.g., two or more different silanes or substituted silanes).

[0072] In some embodiments, the silicon-containing precursor sol from which the silica-based ceramic is derived comprises a silicon-containing precursor comprising a moiety containing an ammonium group or a leaving group (e.g., a halo group). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising a silane (e.g., a substituted alkoxysilane) containing nitrogen (e.g., ammonium). In some embodiments, the silica-based ceramic has the structure (IV): [ka] wherein R 1 , R 2 , and R 3 are independently optionally substituted, C 1~18 L is selected from optionally substituted C 1~18In some embodiments, R is selected from alkylene and arylene, and X is a leaving group. 1 , R 2 , and R 3 each independently represents an optionally substituted C 1~8 L is selected from optionally substituted C 1~8 In some embodiments, R is selected from alkylene and arylene, and X is a leaving group. 1 , R 2 , and R 3 each independently represents an optionally substituted C 1~4 L is selected from optionally substituted C 1~4 and X is a leaving group. In some embodiments, X is selected from chloro, bromo, iodo, tosyl, and trifluoromethanesulfonyl.

[0073] In some embodiments, the silica-based ceramic has the structure (V): [ka] wherein each A 1 is independently selected from hydrogen, methyl, ethyl, propyl, or butyl; n is greater than or equal to 1 and less than or equal to 18; and X is a leaving group (e.g., a leaving group selected from chloro, bromo, iodo, tosyl, and trifluoromethanesulfonyl).

[0074] As an example, in some embodiments, silica-based ceramics are derived from mixtures (e.g., silicon-containing precursor sols) containing (3-chloropropyl)triethoxysilane (3CPTES). As described in more detail below, the resulting silica-based ceramics derived from the leaving group-containing compounds described above can, in some cases, be reacted with amines to form quaternary ammonium groups.

[0075] In some embodiments, the silica-based ceramic has the structure (VI): [ka] wherein R 4 , R 5 , and R 6 are independently optionally substituted C 1~18 L is selected from optionally substituted C 1~18 alkylene and arylene; R 7 , R 8 , and R 9 are independently optionally substituted C 1~18 In some embodiments, R is selected from alkyl, cyclyl, and aryl. 4 , R 5 , and R 6 each independently represents an optionally substituted C 1~8 L is selected from optionally substituted C 1~8 alkylene and arylene; R 7 , R 8 , and R 9 each independently represents an optionally substituted C 1~4 In some embodiments, R is selected from alkyl, cyclyl, and aryl. 4 , R 5 , and R 6 each independently represents an optionally substituted C 1~4 L is selected from optionally substituted C 1~4 alkylene and arylene; R 7 , R 8 , and R 9 each independently represents an optionally substituted C 1~4 It is selected from alkyl, cyclyl, and aryl.

[0076] In some embodiments, the silica-based ceramic has the structure (VII): [ka] wherein A is derived from a mixture (e.g., a silicon-containing precursor sol) containing a compound having the formula 2 is independently selected from hydrogen, methyl, ethyl, propyl, or butyl; n is greater than or equal to 1 and less than or equal to 18; R 10 , R 11 , and R 12 is independently selected from methyl, ethyl, propyl, butyl, cyclohexyl, and benzyl.

[0077] As one example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes trimethoxysilylpropyl-N,N,N-trimethylammonium (TMAPS). As another example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes triethoxysilylpropyl-N,N,N-trimethylammonium (TEAPS).

[0078] In some embodiments, the silica-based ceramic has the structure (VIII): [ka] wherein each R 13 are independently hydrogen or optionally substituted C 1~18 In one embodiment, each R 13 are independently hydrogen or optionally substituted C 1~8 In one embodiment, each R 13 are independently hydrogen or optionally substituted C 1~4 In one embodiment, each R 7 is independently selected from methyl, ethyl, propyl, and butyl.

[0079] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) containing tetraethyl orthosilicate (TEOS) and / or tetraethylorthosiloxane. In some embodiments, the silica-based ceramic is derived from a single-phase mixture (e.g., a single-phase silicon-containing precursor sol) containing both a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., (3-chloropropyl)triethoxysilane). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) containing a compound having structure (VIII), a compound having structure (IV), and water in a molar ratio of structure (VIII):structure (IV):water of 1:0.01-20:1-30, a molar ratio of 1:0.1-10:16, or a molar ratio of 1:0.25-1:2-4. In some embodiments, the silica-based ceramic is derived from a single-phase mixture (e.g., a single-phase silicon-containing precursor sol) containing both a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) containing a compound having structure (VIII), a compound having structure (VI), and water in a molar ratio of structure (VIII):structure (VI):water of 1:0.01-10:1-30, a molar ratio of 1:0.1-10:2-26, or a molar ratio of 1:0.25-1:16-20.

[0080] In some embodiments, the silica-based ceramic is derived from a mixture containing two or more precursors (e.g., a silicon-containing precursor sol). For example, in some embodiments, the silica-based ceramic is derived from a mixture containing a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., 3-chloropropyl)triethoxysilane) in a structure (VIII):structure (IV) weight ratio of 99:1 or less, 95:5 or less, 90:10 or less, 85:15 or less, 80:20 or less, 75:25 or less, 70:30 or less, 65:35 or less, 60:40 or less, or less. In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (IV) (e.g., 3-chloropropyl)triethoxysilane) in a structure (VIII):structure (IV) weight ratio of 50:50 or greater, 55:45 or greater, 60:40 or greater, 65:35 or greater, 70:30 or greater, or greater. Combinations of these ranges are possible (e.g., 50:50 or greater and 99:1 or less, 60:40 or greater and 90:10 or less, or 70:30 or greater and 80:20 or less).

[0081] In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) comprising a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., 3-(trihydroxysilyl)-1-propanesulfonic acid) in a structure (VIII):structure (VI) weight ratio of 99:1 or less, 95:5 or less, 90:10 or less, 85:15 or less, 80:20 or less, 75:25 or less, 70:30 or less, 65:35 or less, 60:40 or less, or less. In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) containing a compound having structure (VIII) (e.g., TEOS) and a compound having structure (VI) (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium) in a structure (VIII):structure (VI) weight ratio of 40:60 or more, 45:55 or more, 50:50 or more, 55:45 or more, 60:40 or more, 65:35 or more, 70:30 or more, or even more. Combinations of these ranges are possible (e.g., 40:60 or more and 99:1 or less, 60:40 or more and 90:10 or less, or 70:30 or more and 80:20 or less).

[0082] In some embodiments, silica-based ceramics are derived from a mixture (e.g., a silicon-containing precursor sol) containing an aqueous solution with a specific pH, depending on the desired chemistry to be used. In some embodiments, the aqueous solution can have a pH of -1 or greater, 0 or greater, 1 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, greater than 6, 7 or greater, 8 or greater, 9 or greater, or greater. In some embodiments, the aqueous solution can have a pH of 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the aqueous solution has a pH of -1 or greater and 14 or less, 0 or greater and 7 or less, or 1 or greater and 3 or less. In some cases, having a relatively acidic pH (e.g., a pH of 1 to 3) can allow certain condensation and hydrolysis reactions to occur during the fabrication of an anion-exchange membrane, including the conversion of a sol-gel to a silica-based ceramic. In certain embodiments, the silica-based ceramic is derived from the above mixture (eg, silicon-containing precursor sol) containing one or more acids, such as, but not limited to, HCl, H3PO4, H2SO4, or HNO3.

[0083] In some, but not necessarily all, embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes one or more other solvents in addition to water. For example, in some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes an alcohol. In some such cases, the presence of an alcohol in the mixture can promote miscibility of the components of the mixture. Exemplary alcohols that may be present include, but are not limited to, methanol, ethanol, isopropanol, butanol, or combinations thereof. In some embodiments, for example, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes methanol (e.g., in some cases, TMAPS is used as a precursor). In some embodiments, the silica-based ceramic is derived from a mixture (e.g., a silicon-containing precursor sol) that includes one or more solvents that may be able to alleviate problems (e.g., cracking) that may occur during drying of a coating that includes the mixture to form the silica-based ceramic. In some embodiments, exemplary solvents that may alleviate such problems include, but are not limited to, formamide and aromatic compounds (e.g., toluene, xylene).

[0084] As described above, in some embodiments, the silica-based ceramic is porous. In some such embodiments, the silica-based ceramic is nanoporous (having pores with an average (mean) diameter of 10 nm or less). The presence of relatively small pores in the silica-based ceramic can be advantageous in some applications, such as electrochemical and separation applications. In some embodiments, the presence of relatively small pores in the silica-based membrane ceramic can contribute to relatively high selectivity (e.g., due to size exclusion) of the anion exchange membrane. The relatively small pores can also contribute to relatively high permselectivity and a useful balance between anion conductivity (e.g., chloride ion conductivity) and water transport. In some embodiments, the silica-based ceramic has an average pore size of 1 μm or less (e.g., 500 nm or less, 100 nm or less, or 50 nm or less). In some cases, the silica-based ceramic has an average pore size of 10 nm or less, 8 nm or less, 6 nm or less, 5 nm or less, 3 nm or less, 2 nm or less, or less. In some embodiments, the silica-based ceramic has an average pore size of 0.25 nm or more, 0.4 nm or more, 0.6 nm or more, or 1 nm or more. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic has an average pore size of 0.25 nm or more and 1 μm or less, 0.25 nm or more and 10 nm or less, 0.4 nanometers or more and 10 nm or less, 0.6 nm or more and 5 nm or less, or 0.6 nm or more and 2.5 nm or less.

[0085] The average pore size of silica-based ceramics can be determined using small-angle X-ray scattering (SAXS) techniques. In a suitable SAXS technique, a collimated X-ray beam is focused on a film comprising a silica-based ceramic for at least 15 minutes, and the scattered intensity as a function of scattering angle is collected on an image plate. The scattered intensity is integrated to generate a one-dimensional scattering profile that plots the scattered intensity as a function of the q-vector. The scattering of the film can be fitted with a sphere-based shape factor (e.g., solid or core-shell). In some cases, the sphere-based shape factor can include structure factors (e.g., fractal or hard-sphere interactions). The fit can be performed in the freely available SASView software. A log-normal distribution in pore size polydispersity is assumed. The model and data set (Chi 2 ) is less than or equal to 10, less than or equal to 1, less than or equal to 0.5, or less than or equal to 10. The 1-D SAXS profile is assumed to be well-fit. solvent =18.8×10 -6 Å -2 and SLD sphere =0Å -2Certain parameters are held constant during the fit, including: where SLD is the scattering length density. The SAXS fit can be used to determine the void volume fraction, pore size (e.g., average pore size), and the polydispersity index of the pore size distribution. Suitable SAXS procedures are described in detail, for example, in Pedersen, J.S., Analysis of small-angle scattering data from colloids and polymer solutions: modeling and least-squares fitting. Advances in Colloid and Interface Science 1997, 70, 171-210, and Zemb., T.; Lindner, P., Neutron, X-Rays and Light. Scattering Methods Applies to Soft Condensed Matter. North Holland: 2002, which are incorporated herein by reference in their entirety. The average pore size can also be determined using other small-angle scattering techniques, such as small-angle neutron scattering (SANS).

[0086] In some embodiments, the anion exchange membrane or material has a relatively high volume porosity. The volume porosity may depend on the porosity of the silica-based ceramic. Having a relatively high volume porosity may contribute to certain beneficial performance characteristics of the anion exchange membrane, such as anion exchange capacity and water absorption. In some embodiments, the anion exchange membrane or material has a volume porosity of 1% or more, 3% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, or more. In some embodiments, the anion exchange membrane or material has a volume porosity of 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 15% or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the anion exchange membrane or material has a volume porosity of 1% or more and 70% or less, 5% or more and 50% or less, 10% or more and 50% or less, or 30% or more and 50% or less. As described above, these volume porosities of the anion exchange membrane or material are determined by fitting SAXS data of the anion exchange membrane or material.

[0087] In some embodiments, the pores in the silica-based ceramic have a relatively small aspect ratio (length:width). The aspect ratio of the pores in the silica-based film can be determined by fitting the SAXS data to an ellipsoidal model and taking the ratio of the average first and average second radii to determine the average first and average second radii of the pores in the silica-based film. In some embodiments, the pores in the silica-based film have an aspect ratio of 40:1 or less, 20:1 or less, 10:1 or less, 5:1 or less, or less.

[0088] In certain embodiments, the pores of the silica-based ceramic have an ordered structure. Such an ordered structure may, in some cases, be in contrast to the pores of certain existing anion-exchange membranes, such as those made from hydrocarbon- or perfluorocarbon-based polymers, which may have string-like, irregular pores (e.g., with high polydispersity). Having silica-based ceramics with regular, ordered pores over a relatively large size scale may, in some cases, correspond to improved performance characteristics in anion-exchange applications. The pores of silica-based ceramics are characterized by scattering data from SAXS experiments on membranes or materials containing silica-based ceramics that have a Chi of 10 or less, 5 or less, 1 or less, 0.5 or less, or even less. 2 / N value, and can be fitted to a mathematical model such as a fractal aggregate model, where Chi 2 is the sum of squares of the intensity differences between the mathematical model and the small-angle scattering spectral data, and N is the number of small-angle scattering data points over the model fit range. An exemplary fractal aggregate model using SAXS data of intensity (I) as a function of the scattering vector, q, is as follows: I(q)=P(q)S(q)+bck S(q) is a network or fractal structure that defines the organization or organization of the building blocks of the pore network of the silica-based ceramic. In other words, in some embodiments, the building blocks are the pores of the silica-based ceramic. Bck defines the background scattering, e.g., from the scattering particle source and / or the inelastic scattering of the scattering particles from the silica-based ceramic. In some embodiments, S(q) is expressed by the following formula:

number

[0089] P(q) is the shape factor that defines the structure of the building blocks of the pore network of silica-based ceramics as a function of q. Such shape factors can take on a variety of shapes, including simple geometric shapes such as spheres, ellipsoids, cubes, and ovals.

[0090] In some embodiments, the building blocks (pores) are defined as uniform building blocks, such as uniform spheres. In that regard, in some embodiments, P(q) is defined as follows: P(q) = scale × V(ρ block -ρ solvent ) 2 F(qR0) 2 is defined by:

number

[0091] In some embodiments, the shape factor defines a spherical core-shell building block (pore). In some such embodiments, P(q) is expressed as:

number

[0092] In some embodiments, one or more surfaces of the silica-based ceramic are coated with an additional coating. A core-shell model, such as a core-shell fractal aggregate model, may be suitable for characterizing the core-shell particle building blocks. In some cases, the core-shell model is suitable even in the absence of an additional coating process. For example, in some embodiments, the method used to form the silica-based ceramic (e.g., a sol-gel-based method) produces phase-separated regions that can be modeled using the core-shell model.

[0093] As noted above, various embodiments of the shape factor, P(q), of the fractal aggregate model used to characterize small-angle scattering spectra can include factors that account for differences between scattering length densities.

[0094] In some embodiments, the scattering length density in the above formula is defined by the materials that make up the components of the silica-based ceramic film. Generally, the greater the difference between the scattering length densities of scattering sources such as pores, the greater the scattering contrast provided by the surrounding ceramic material. Thus, in some embodiments, small-angle scattering data is generated from a silica-based ceramic that has been dried to remove solvent or other liquid from the pores, thus resulting in a greater difference in scattering length density compared to a silica-based ceramic with pores filled with a liquid solvent.

[0095] In certain embodiments, the scattering length density is -2 The scattering length density is defined as the sum of the bond coherent scattering lengths of each atom normalized by the molecular volume. For example, the X-ray scattering length density of air is approximately 0 Å. -2 On the other hand, the X-ray scattering length density of amorphous silica is about 18.8 × 10 -6 Å -2 is.

[0096] In one embodiment, small-angle scattering data is generated from a silica-based ceramic that has been rinsed to remove residual ions, chemical reactants, and the like.

[0097] In certain embodiments, fitting the small-angle scattering spectrum to the fractal aggregate model includes fitting the small-angle scattering spectrum over a range of q values ​​of more than one order of magnitude, e.g., over one order of magnitude, where q is Å -1 In addition to providing sufficient data to fit the fractal aggregate model, such a relatively wide fit range can ensure that the data fit the fractal aggregate model over a size range commensurate with the size scale of pores in, for example, silica-based ceramics. In certain embodiments, the fit of the small-angle scattering spectrum to the fractal aggregate model is within a range of about 0.01 Å. -1 ~approximately 1 Å -1 In one embodiment, the fitting of the small-angle scattering spectrum to the fractal aggregate model includes fitting the small-angle scattering spectrum over a range of q values ​​in the range of about 0.02 Å. -1 ~approx. 0.8Å -1 This involves fitting small-angle scattering spectra over a range of q values ​​in the range

[0098] As noted above, the scale corresponds to the volume fraction of pores in the silica-based ceramic. In some embodiments, the scale corresponds to the film porosity when the small-angle scattering spectrum has intensity units of 1 / cm, and the scale is less than 0.7. In this context, the scale corresponds to the number of pores normalized by the size of the sample. In some embodiments, the silica-based ceramic has a pore volume fraction in the range of about 0.01 to about 0.7. In some embodiments, the silica-based ceramic has a pore volume fraction in the range of about 0.15 to about 0.35. It should be understood that the above ranges correspond to the scattering length density of air at ambient conditions for the pores of the silica-based ceramic and amorphous silica, respectively.

[0099] In one embodiment, D f is the fractal dimension of the fractal aggregate model described herein. In some embodiments, D fcorresponds to the shape and / or configuration of the pores within the silica-based ceramic. f is in the range of about 1 to about 3. f is close to or equal to 1, the pore can generally be characterized as a one-dimensional tunnel. f is close to or equal to 3, the pore may generally be characterized as an open sphere.

[0100] In certain embodiments, it is advantageous to have a silica-based ceramic that defines pores that have a tortuous or tortuous path through the silica-based ceramic. In the case of ions or other particles in fluid communication with the tortuous pores, the ions or other particles are less likely to traverse the membrane as the size of the ions or other particles approaches that of the tortuous pores compared to less tortuous pores. In this regard, such silica-based ceramics that define tortuous pores may in some cases be suitable for, e.g., providing more selective anion exchange than silica-based ceramics that define pores of the same size but that provide a more direct path through the silica-based ceramic. In this regard, in some, but not necessarily all, embodiments, D f is in the range of 2.0 to 4.0. f The range describes or characterizes silica-based ceramics with relatively intricate pores having a shape factor somewhere between a straight line and an open sphere.

[0101] In some embodiments, the fractal aggregate model is constrained to have pore sizes within a particular range. As described above, the porous support defines pores having an average pore size within the range. Similarly, the methods described in the present disclosure are suitable for producing such silica-based ceramics that define pores within this size range. Therefore, by constraining the fractal aggregate model used to fit the small-angle scattering data, a good fit between the fractal silica-based ceramic and the fractal aggregate model can be obtained.

[0102] As noted above, the correlation length, ξ, is the length at which the fractal pattern of a silica-based ceramic repeats itself. In some cases, the silica-based ceramic repeats the fractal pattern over relatively large size scales. In this regard, such silica-based ceramics define regular, ordered pores over relatively large size scales, which may, in some cases, correspond to improved functional properties such as filtration, ion exchange, and the like. Similarly, fractal patterns generally cannot be extended to size scales smaller than the size scale of the constituent units of the silica-based ceramic, e.g., submolecular or atomic size scales. Thus, in some embodiments, the correlation length, ξ, is constrained to a value greater than 1 nm. In some embodiments, the correlation length, ξ, is constrained to a value greater than 50 nm. In some embodiments, the correlation length, ξ, is constrained to a value greater than 100 nm. In some embodiments, the correlation length, ξ, is constrained to a value approximately equal to the thickness of the silica-based ceramic. In some embodiments, the silica-based ceramic has a correlation length, ξ, greater than 1 nm, e.g., greater than 50 nm or greater than 100 nm.

[0103] The fractal aggregate model used to characterize silica-based ceramics may include a term to account for the variability in the size of scattering sources, such as pores, in silica-based ceramics. In this regard, in some embodiments, the fractal aggregate model includes a polydispersity index in the radius parameter. Thus, in some embodiments, the radius of the constituent units, R o is a weighted average rather than a constant. The weighted average can follow several mathematical functions, such as a Gaussian function, a log-normal function, a rectangular distribution, etc. In certain embodiments, the polydispersity index is a Gaussian function, as follows:

number

[0104] In certain embodiments, the polydispersity ratio is a lognormal function, as follows:

number

[0105] In one embodiment, the lognormal distribution is generally x med In this regard, as the polydispersity ratio increases, the lower tail, e.g., atoms that physically define the pore, which may define a smaller pore diameter, may not fall within the aphysical range.

[0106] In some embodiments, the pores of the silica-based ceramic have a relatively low log-normal polydispersity index of pore radius. A relatively low log-normal polydispersity index of pore radius generally corresponds to pores having relatively similar radii, which may indicate a regular ordered structure of the pores of the silica-based ceramic. In some embodiments, the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius of 0.8 or less, 0.7 or less, 0.5 or less, 0.3 or less, or less. In some embodiments, the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius of 0 or more and 0.8 or less, 0 or more and 0.7 or less, 0 or more and 0.5 or less, or 0 or more and 0.3 or less.

[0107] In certain embodiments, the pores of silica-based ceramics conform to the Teubner-Strey model. The Teubner-Strey model was originally developed to describe the scattering patterns and microstructure of microemulsions (e.g., mixtures of water, oil, and amphiphiles). Small-angle scattering experiments, such as small-angle neutron scattering (SANS) experiments, have unexpectedly revealed that, in embodiments, anion-exchange membranes or materials herein possess silica-based ceramic pore structures that conform to such a Teubner-Strey model. Teubner-Strey ordering is more commonly associated with packed micellar structures, where micelles reinforce distinct pore structures and interpore distances, rather than in the ceramic-based structures observed herein.

[0108] When the pores of a silica-based ceramic fit the Teubner-Strey model for small-angle scattering spectra, the intensity (I) as a function of the scattering vector, q, is given by the following equation:

number

[0109] The Teubner-Strey fit of small angle scattering from pores in silica-based ceramics is also given by:

number

[0110] In some, but not necessarily all, embodiments, the pore structure of a silica-based ceramic depends on the state of the anion exchange membrane or material. For example, whether the anion exchange membrane is in a dry or hydrated state can affect the pore structure of the silica-based ceramic in some cases. The pores of the silica-based ceramic can fit a first mathematical model of small-angle scattering spectra when the anion exchange membrane or material is in a first state (e.g., a dry state), and the pores of the silica-based ceramic can fit a second, different mathematical model of small-angle scattering spectra when the anion exchange membrane or material is in a second, different state (e.g., a hydrated state). In this regard, an anion exchange membrane or material is considered to be in a dry state when heated in an oven at 100°C and 0% relative humidity for 2 hours, and an anion exchange membrane or material is considered to be in a hydrated state when immersed in H2O or D2O at room temperature for 24 hours in a vacuum environment with a reduced pressure to remove air from the pores but not low enough to boil the H2O or D2O.

[0111] As another example, in some, but not necessarily all, embodiments, the average pore size of a silica-based ceramic is larger when the anion exchange membrane or material is in a hydrated state compared to when the anion exchange membrane or material is in a dry state. It has been observed that having an average pore size in the hydrated state that is larger than the average pore size in the dry state can result in percolation of hydrated domains in the silica-based ceramic. Such percolation can result in improved anion transport properties (e.g., chloride ion conductivity). In some embodiments, the silica-based ceramic has an average pore size that is 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, 1.5 times or more, 1.6 times or more, 1.8 times or more, 2 times or more, or more larger when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state. In some embodiments, the silica-based ceramic has an average pore size that is at most 5 times, at most 4.5 times, at most 4 times, at most 3.5 times, at most 3 times, at most 2.8 times, at most 2.6 times, at most 2.5 times, at most 2.4 times, at most 2.3 times, at most 2.2 times, at most 2.1 times, at most 2 times, or at most not more than ...

[0112] As another example, in some, but not necessarily all, embodiments, the pores of a silica-based ceramic conform to the Teubner-Strey model of the above-described small-angle scattering spectrum when the anion exchange membrane or material is in a dry state, and the pores of a silica-based ceramic conform to the core-shell model of the above-described small-angle scattering spectrum when the anion exchange membrane or material is in a hydrated state. In certain embodiments, it has been observed that having Teubner-Strey ordering in the dry state and a core-shell structure in the hydrated state is associated with structural changes upon water absorption that confer beneficial performance properties (e.g., anion exchange capacity, anion conductivity, permselectivity, etc.).

[0113] Whether the pore structure of a silica-based membrane depends on the state of the anion exchange membrane or material may depend on the composition of the silica-based membrane or material and / or the conditions under which the anion exchange membrane or material is fabricated. For example, the dependence of the pore structure on the state (e.g., dry vs. hydrated) of the anion exchange membrane or material may depend on the amount of functional groups (e.g., sulfonic acid and / or sulfonate groups) present in the silica-based ceramic. The amount of functional groups present may in turn depend on the ratio of silicon-containing precursors, for example, in a silicon-containing precursor sol, during fabrication of the anion exchange membrane or material. In certain embodiments, anion exchange membranes derived from a silicon-containing precursor sol having a relatively small amount (e.g., 5 mol % or less, 1 mol % or less, or less) of silicon-containing precursors containing functional groups (e.g., having structure IV or VI) have relatively similar pore structures (e.g., average pore size, small-angle scattering model fit) regardless of whether the anion exchange membrane or material is in a dry or hydrated state. For example, in some such cases, the average pore size in the hydrated state is within 10%, 5%, or 2% of the average pore size in the dry state. However, in some embodiments, an anion exchange membrane derived from a silicon-containing precursor sol having a relatively large amount (e.g., 15 mol% or more, 20 mol% or more, 25 mol% or more, 30 mol% or more, 35 mol% or more, 40 mol% or more) of silicon-containing precursors containing functional groups (e.g., having structure IV or VI) has a pore structure (e.g., average pore size, small-angle scattering model fit) that is substantially different when the anion exchange membrane or material is in a dry state compared to when it is in a hydrated state (e.g., the pore size in the hydrated state is 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, 2 times or more larger than the pore size in the dry state).

[0114] As described above, in certain embodiments, the anion exchange membrane comprises a porous support membrane. The porous membrane (e.g., porous support membrane 130) can comprise any of a variety of suitable materials and can be in any of a variety of forms.

[0115] In some embodiments, the porous support membrane comprises relatively large pores in the absence of the silica-based ceramic, e.g., before being coated with the silica-based ceramic. For example, referring again to FIG. 2A, porous support membrane 130 comprises pores, including relatively large pores 132. Having relatively large pores can, in some embodiments, allow sufficient overall permeability across the membrane as well as sufficient space for the silica-based ceramic to reside when the coating formed by the silica-based ceramic is at least partially located within the porous membrane support. In some embodiments, the porous support membrane comprises pores having an average (mean) pore size in the absence of the silica-based ceramic, e.g., 50 nm or more, 75 nm or more, 100 nm or more, 200 nm or more, 500 nm or more, 1 μm or more, 2 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or more, before being coated with the silica-based ceramic. However, in some embodiments, the porous support membrane does not contain pores so large that they adversely affect the performance or properties of the anion-exchange membrane (e.g., low mechanical burst strength, low coating retention, etc.). In some embodiments, the porous support membrane contains pores having an average pore size, prior to coating with the silica-based ceramic and in the absence of the silica-based ceramic, of, for example, 50 μm or less, 25 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane contains pores having an average diameter, prior to coating with the silica-based ceramic, of, for example, 50 nm or more and 50 μm or less, 500 nm or more and 10 μm or more, or 1 μm or more and 5 μm or less. The average pore size of the porous support membrane in the anion-exchange membrane can be determined by Brunauer-Emmett-Teller (BET) gas sorption technique or mercury intrusion porosimetry.

[0116] It should be understood that in some embodiments, the silica-based ceramic, if present, fills at least some (or all) of the pores of the porous support membrane. In such cases, the average pore size of the porous support membrane in the final anion-exchange membrane is smaller than the average pore size of the porous support membrane before being coated with the silica-based ceramic. Furthermore, as described above, in some embodiments, the silica-based ceramic itself is porous (e.g., nanoporous). Thus, in some embodiments, the anion-exchange membrane has a bimodal distribution of pores. For example, in some embodiments, the anion-exchange membrane has a bimodal distribution of pores, including relatively small pores corresponding to the pores of the silica-based ceramic and relatively large pores corresponding to partially filled (e.g., 70% filled) pores of the porous support membrane. In these embodiments, the bimodal distribution can be determined by measuring the relatively small pores using the SAXS techniques described above (e.g., to measure the pores corresponding to the silica-based ceramic) and measuring the relatively large pores using the BET gas sorption or mercury intrusion porosimetry techniques described above (e.g., to measure the pores corresponding to the partially filled pores of the porous support membrane).

[0117] In some embodiments, the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) has an average pore size of 1 μm or less (e.g., 500 nm or less, 100 nm or less, or 50 nm or less). In some cases, the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) has an average pore size of 10 nm or less, 8 nm or less, 6 nm or less, 5 nm or less, 3 nm or less, 2 nm or less, or less. In some embodiments, the bimodal distribution of relatively small pores (e.g., corresponding to the pores of the silica-based ceramic) has an average pore size of 0.25 nm or more, 0.4 nm or more, 0.6 nm or more, or 1 nm or more. Combinations of these ranges are possible. For example, in some embodiments, the bimodal distribution of relatively small pores (e.g., corresponding to the pores of a silica-based ceramic) has an average pore size of 0.25 nm or more and 1 μm or less, 0.25 nm or more and 10 nm or less, 0.4 nanometers or more and 10 nm or less, 0.6 nm or more and 5 nm or less, or 0.6 nm or more and 2.5 nm or less.

[0118] In some embodiments, the bimodal distribution of larger pores (e.g., corresponding to partially filled pores in the porous support membrane) has an average pore size of 50 nm or more, 75 nm or more, 100 nm or more, 200 nm or more, 500 nm or more, 1 μm or more, 2 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or more. In some embodiments, the bimodal distribution of larger pores (e.g., corresponding to partially filled pores in the porous support membrane) has an average pore size of 50 μm or less, 25 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the bimodal distribution of larger pores (e.g., corresponding to the partially filled pores of the porous support membrane) has an average pore size of 50 nm or more and 50 μm or less, 500 nm or more and 10 μm or less, or 1 μm or more and 5 μm or less.

[0119] In some embodiments, the porous support membrane has a relatively high volume porosity in the absence of the silica-based ceramic, for example, before being coated with the silica-based ceramic. Having a relatively high volume porosity can, in some cases, allow sufficient overall permeability and sufficient space for the silica-based ceramic to reside when the coating formed by the silica-based ceramic is at least partially located within the porous membrane support. In some embodiments, for example, the porous support membrane in the absence of the silica-based ceramic, before being coated with the silica-based ceramic, has a volume porosity of 10% or more, 15% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or more. In some embodiments, the porous support membrane has a volume porosity in the absence of the silica-based ceramic of, for example, 99% or less, 95% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane in the absence of the silica-based ceramic, e.g., before being coated with the silica-based ceramic, has a volume porosity of 10% or more and 99% or less, 50% or more and 99% or less, 80% or more and 99% or less, or 60% or more and 80% or less. It should be understood that in some embodiments, the silica-based ceramic fills at least a portion of the pores of the porous support membrane. Thus, in some embodiments, the entire anion-exchange membrane can have a volume porosity that is different from the volume porosity of the porous support membrane in the absence of the silica-based ceramic. The volume porosity of the porous support membrane in the anion-exchange membrane can be determined by BET gas sorption techniques or mercury intrusion porosimetry.

[0120] The porous support membrane can have any suitable cross-sectional thickness. Having a suitable cross-sectional thickness can, in some cases, enable the porous support membrane, and ultimately the anion exchange membrane, to have suitable mechanical properties (e.g., mechanical burst strength) and performance characteristics (e.g., by having appropriate permeability and ion transport rate). In certain embodiments, the porous support membrane has a cross-sectional thickness of 3 μm or more, 5 μm or more, 10 μm or more, 25 μm or more, 50 μm or more, 75 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, 400 μm or more, 500 μm or more, or more. In certain embodiments, the porous support membrane has a cross-sectional thickness of 1,000 μm or less, 500 μm or less, 300 μm or less, 100 μm or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane has a cross-sectional thickness of 3 μm or more and 1,000 μm or less, or 25 μm or more and 300 μm or less. The cross-sectional thickness of the porous support membrane in an anion exchange membrane can be determined using SEM / EDX techniques on the anion exchange membrane. In some embodiments, the EDX component of the technique can be used to distinguish the porous support membrane from other components of the anion exchange membrane, such as silica-based ceramics.

[0121] The porous support membrane can be in any of a variety of suitable forms. Accordingly, it should be understood that the representation of the porous support membrane 130 in FIG. 2A is non-limiting and exemplary, and that the porous support membrane 130 can be in the form of any suitable structure. In certain embodiments, the porous support membrane can be in the form of a macroporous structure. For example, in certain embodiments, the porous support membrane is in the form of a nonwoven fabric or nonwoven mesh. In certain embodiments, the porous support membrane is in the form of a veil. In certain embodiments, the porous support membrane is in the form of a knitted fabric. In some cases, the porous support membrane is in the form of a woven fabric or mesh. In certain embodiments, the porous support membrane is in the form of an open-cell structure, such as an open-cell foam. In certain embodiments, the porous support membrane is in the form of a fibril and node structure. In some cases, the porous support membrane comprises a combination of multiple types of microporous structures. For example, in certain embodiments, the porous support membrane comprises a combination of the exemplary structures described above (e.g., a nonwoven fabric, an open-cell foam, etc.).

[0122] The porous support membrane can be formed by any suitable method, hi some embodiments, the porous support membrane is a wet-laid or non-wet-laid structure (e.g., airlaid, carded, meltblown, meltspun (e.g., spunbond), centrifugally spun, solvent spun, electroblown, or gel-spun web).

[0123] As described above, in some embodiments, the porous support membrane includes a support component. The support component of a porous support membrane generally refers to a component of the porous support membrane that contributes to the overall structure and mechanical properties of the porous support membrane. For example, in some embodiments where the porous support membrane is in the form of a nonwoven fabric, the support component of the nonwoven fabric may include the fibers and / or filaments from which the nonwoven fabric is formed. As another example, in some embodiments where the porous support membrane is in the form of a mesh, the support component of the mesh may include the yarns from which the mesh is formed. Examples of support components include, but are not limited to, fibers, yarns, and wires. Referring again to FIG. 2A , the porous support membrane 130 includes an exemplary porous support component 135, according to some embodiments.

[0124] In some embodiments, the support elements have a relatively large number-average diameter. In some cases, having a support element with a relatively large diameter can contribute to a porous support membrane having relatively beneficial mechanical properties (e.g., relatively high mechanical burst strength). In some embodiments, the porous support membrane has a number-average support element diameter (e.g., fiber diameter, cell diameter) of 10 nm or more, 25 nm or more, 50 nm or more, 100 nm or more, 200 nm or more, 500 nm or more, 1 μm or more, 2 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, or more. In some embodiments, the support elements of the porous support membrane are not so large as to contribute to adverse effects in the overall anion exchange membrane, such as insufficient porosity or permeability. In some embodiments, the porous support membrane has a number-average support element diameter (e.g., fiber diameter, cell diameter) of 50 μm or less, 20 μm or less, 10 μm or less, 5 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 100 nm or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the porous support membrane has a number average support element diameter of ≧10 nm and ≦50 μm, ≧10 nm and ≦20 μm, ≧100 nm and ≦1 μm, or ≧100 nm and ≦500 nm.

[0125] The porous support membrane can comprise any of a variety of suitable materials (e.g., organic materials, inorganic materials, or combinations thereof). In some embodiments, the porous support membrane comprises a polymeric material. In some such cases, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 90% or more, 95% or more, or more by weight of the porous support membrane is composed of one or more polymers. In some embodiments, 100% or less, 99% or less, 95% or less, 90% or less, 80% or less, 50% or less, 30% or less, or less by weight of the porous support membrane is composed of one or more polymers. Combinations of these ranges are possible. For example, in some embodiments, 20% or more and 100% or less, or 50% or more and 99% or less by weight of the porous support membrane is composed of one or more polymers. Exemplary polymers that the porous support membrane may comprise include, but are not limited to, polyethylene, polyvinyl chloride, polypropylene, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyetheretherketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, microfibrillated cellulose, nanofibrillated cellulose, or combinations or derivatives thereof.

[0126] In some embodiments, the porous support membrane comprises a ceramic or glass material. In some such cases, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or more by weight of the porous support membrane is composed of one or more ceramic or glass materials. In some embodiments, 100% by weight or less, 99% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 50% by weight or less, 30% by weight or less, or less by weight of the porous support membrane is composed of one or more ceramic or glass materials. Combinations of these ranges are possible. For example, in some embodiments, 20% by weight or more and 100% by weight or more, or 50% by weight or more and 99% by weight or more, of the porous support membrane is composed of one or more ceramic or glass materials. Exemplary ceramics that the porous support membrane may comprise include, but are not limited to, borosilicate glass, silica, titania, zirconia, alumina, silicon carbide, silicon nitride, boron nitride, lithium silicate, potassium silicate, tin oxide, iron oxide, or combinations thereof.

[0127] In some embodiments, the porous support membrane comprises a metal and / or metal alloy. In some such cases, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 75% or more, 80% or more, 90% or more, 95% or more, or more by weight of the porous support membrane is composed of one or more metals and / or metal alloys. In some embodiments, 100% or less, 99% or less, 95% or less, 90% or less, 80% or less, 50% or less, 30% or less, or less by weight of the porous support membrane is composed of one or more metals and / or metal alloys. Combinations of these ranges are possible. For example, in some embodiments, 20% or more and 100% or less, or 50% or more and 99% or less by weight of the porous support membrane is composed of one or more metals and / or metal alloys. Exemplary metals that the porous support membrane may comprise include, but are not limited to, iron, nickel, copper, titanium, aluminum, or combinations thereof. One non-limiting example of a metal alloy that the porous support membrane may comprise is steel.

[0128] In some embodiments, the porous support membrane comprises a combination of the above materials. For example, in some embodiments, the porous support membrane comprises a combination of a polymeric material and a ceramic or glass material (or a polymeric material and a metal and / or metal alloy, or a ceramic material and a metal and / or metal alloy). One non-limiting example is an embodiment in which the porous support membrane comprises a glass material (e.g., borosilicate glass) containing one or more polymeric materials (e.g., one or more polymeric binders that can enhance the mechanical properties of the porous support membrane).

[0129] In some, but not necessarily all, embodiments, the porous support membrane includes one or more amphiphilic molecules on its surface. Including one or more amphiphilic molecules on the surface of the porous support membrane can, in some cases, promote increased wetting of solutions used during fabrication of the anion exchange membrane. For example, in some cases, the anion exchange membrane is fabricated by applying a sol-gel solution to the porous support membrane. In some cases, such increased wetting can contribute to reduced cracking during certain fabrication processes, such as when a drying step is performed. In some such cases, having one or more amphiphilic molecules present on the surface of the porous support membrane can promote wetting of the sol-gel ceramic material in the porous support membrane. In some cases, the amphiphilic molecules are covalently bonded to at least a portion of the porous support membrane (e.g., as surface functional groups). In some embodiments, the amphiphilic molecules are coated on or within the porous support membrane (e.g., prior to coating the porous support membrane with the sol-gel). Exemplary amphiphilic molecules include, but are not limited to, sodium alkyl sulfates (e.g., sodium dodecyl sulfate), dialkyl sulfosuccinates, and alkyltrimethylammonium bromides.

[0130] In certain embodiments, the porous support membrane has a relatively high surface area (e.g., before being coated with a silica-based ceramic). Having a relatively high surface area of ​​the porous support membrane can, in some cases, promote adhesion between the porous support membrane and the silica-based ceramic. One exemplary way in which a relatively high surface area of ​​the porous support membrane can be achieved is by etching the porous support membrane before coating it with a silica-based ceramic. The porous support membrane can, in some cases, be etched with a suitable solvent, acid, caustic, or oxidizing agent. In certain embodiments, the porous support membrane has a surface area of ​​0.0001 m before being coated with a silica-based ceramic. 2 / g or more, 0.0002m 2 / g or more, 0.0005m 2 / g or more, 0.001m 2 / g or more, 0.002m 2 / g or more, 0.005m 2 / g or more, 0.01m 2 / g or more, 0.02m 2 / g or more, 0.05m 2 / g or more, 0.1m 2 / g or more, 0.2m 2 / g or more, 0.5m 2 In some embodiments, the porous support membrane has a specific surface area of ​​100 m / g or more before being coated with the silica-based ceramic. 2 / g or less, 50m 2 / g or less, 20m 2 / g or less, 10m 2 / g or less, 5m 2 / g or less, 2m 2 / g or less, 1m 2 / g or less, or even less. Combinations of these ranges are possible. For example, in one embodiment, the porous support membrane has a specific surface area of ​​0.0001 m / g or less before being coated with the silica-based ceramic. 2 / g or more and 100m 2 / g or less, 0.001m 2 / g or more and 10m 2 / g or less, or 0.01m 2 / g or more and 1m 2 The specific surface area of ​​the porous support membrane before being coated with the silica-based ceramic can be determined using BET gas sorption techniques (either before the silica-based ceramic coating is formed or by removing the silica-based ceramic from the anion exchange membrane).

[0131] In some embodiments, a relatively high percentage of the pore volume of the porous support membrane is filled with a silica-based ceramic that coats at least a portion of the porous support membrane. The percentage of the pore volume of the porous support membrane that is filled with the silica-based ceramic can be determined, for example, using an SEM. Typically, several images are taken from both the top and cross-section of the anion-exchange membrane at various magnifications, ranging from 200x for the top to 2000x for the cross-section. These images can be compared with images of the porous support membrane at the same magnification. A cross-section of the anion-exchange membrane is examined to determine the extent to which the pore volume of the porous support membrane is filled with the silica-based ceramic. Anion-exchange membranes in which the pore volume of the porous support membrane is sufficiently filled with the silica-based ceramic appear dense and have few to no apparent macropores or openings. In some cases, it can be beneficial if there are areas of low density (e.g., cracks, smaller pores, etc.) that are not structured to create clear paths for liquid to move from one side of the anion-exchange membrane to the other. Similarly, in some embodiments, it may be beneficial for the anion exchange membrane to have an image of the top of the membrane that appears smooth and uniform. In some embodiments, it may be beneficial for the membrane to have a relatively small surface area of ​​silica-based ceramic. The surface area of ​​silica-based ceramic in the anion exchange membrane may be determined by examining an SEM of an area of ​​silica-based ceramic on the top or bottom surface of the porous support membrane. In some embodiments, the surface area of ​​silica-based ceramic on the top of the porous support membrane is 200 μm or less, 20 μm or less, 2 μm or less, or less, as determined by SEM.

[0132] In some embodiments, the pore volume of the porous support membrane is filled with at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.9%, and / or up to 100% of the pore volume. In some embodiments, the pore volume of the porous support membrane is filled with at most 100%, at most 99.9%, at most 99%, at most 98%, at most 97%, at most 96%, at most 95%, at most 90%, at most 80%, at most 75%, at most 70%, or at most 60% of the pore volume. Combinations of these ranges are possible. For example, in some embodiments, 50% to 100%, 75% to 100%, 90% to 100%, or 97% to 100% of the pore volume of the porous support membrane is filled with silica-based ceramic as determined by SEM. For example, SEM images can be acquired for a representative number of cross sections (e.g., at least three cross sections) of different regions of the membrane sample. Image processing software (e.g., ImageJ) can then be used to enhance the contrast between the void regions (which typically appear black in the image) and the filled regions (which typically appear gray in the image), and the area of ​​the void regions can be divided by the total area probed. A sufficiently large sample size (approximately 0.5 cm in the image) can be used to enhance the contrast between the void regions and the filled regions (which typically appear gray in the image) and divide the area of ​​the void regions by the total area probed. 2 ), one can determine the total "gap area" relative to the total area of ​​the cross section. It may be important to take cross sections from multiple regions of the membrane to obtain a somewhat representative sample.

[0133] The anion exchange membrane can have any suitable thickness. For example, referring to FIG. 1A , anion exchange membrane 100 has thickness 154. The thickness of the anion exchange membrane can be selected based on, for example, the intended use of the anion exchange membrane or the geometry of the device (e.g., electrochemical device, filtration device, etc.) into which the anion exchange membrane will be incorporated. In certain embodiments, the anion exchange membrane has a thickness of 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 25 μm or more, 50 μm or more, 100 μm or more, 200 μm or more, 300 μm or more, 400 μm or more, 500 μm or more, 700 μm or more, 1,000 μm or more, 1,200 μm or more, or more. In some embodiments, the anion exchange membrane has a thickness of 1,500 μm or less, 1,000 μm or less, 500 μm or less, 300 μm or less, 100 μm or less, 75 μm or less, 50 μm or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the porous support membrane has a cross-sectional thickness of 1 μm or more and 1,500 μm or less, or 25 μm or more and 300 μm or less. The thickness of the porous support membrane in the anion exchange membrane can be determined by photographing an SEM cross-section of the anion exchange membrane or by using calipers.

[0134] In some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion-exchange membrane is 1:10 or more, 1:5 or more, 1:2 or more, 1:1 or more, 2:1 or more, 5:1 or more, 10:1 or more, 20:1 or more, 35:1 or more, 50:1 or more, 75:1 or more, 100:1 or more, or more. In some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion-exchange membrane is 300:1 or less, 250:1 or less, 220:1 or less, 200:1 or less, 150:1 or less, 120:1 or less, 100:1 or less, 75:1 or less, 50:1 or less, 35:1 or less, 20:1 or less, 10:1 or less, 5:1 or less, 2:1 or less, 1:1 or less, 1:2 or less, 1:5 or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the weight ratio of the silica-based ceramic to the porous support membrane in the anion exchange membrane is 1:10 or more and 300:1 or less, or 1:2 or more and 220:1 or less.

[0135] In one embodiment, the anion exchange membrane has a density of 0.8 g / cm 3 More than 0.9g / cm 3 More than 1.0g / cm 3 More than 1.2g / cm 3 More than 1.5g / cm 3 More than 1.8g / cm 3 In some embodiments, the anion exchange membrane has a density of 2.2 g / cm or greater. 3 Below, 2.1g / cm 3 Below 2.0g / cm 3 Below, 1.9g / cm 3 Below 1.8g / cm 3 Below, 1.7g / cm 3 Below, 1.6g / cm 3 Below 1.5g / cm 3 Below, 1.2g / cm 3 Combinations of these ranges are possible. For example, in one embodiment, the anion exchange membrane has a density of 0.8 g / cm or less. 3 or more and 2.2 g / cm 3 or less, or 1.0 or more and 2.0 g / cm 3 It has the following density:

[0136] In one embodiment, the anion exchange membrane has a thickness of 320 g / m 2 More than 350g / m 2 More than 400g / m 2 More than 450g / m 2 More than 500g / m 2 More than 550g / m 2 More than 600g / m 2 In some embodiments, the anion exchange membrane has a basis weight of 880 g / m or more. 2 Below 850g / m 2 Below 800g / m 2 Below 750g / m 2 Below 700g / m 2 Below 650g / m 2 Below 600g / m 2 Below 550g / m 2 Below 500g / m2 Combinations of these ranges are possible. For example, in one embodiment, the anion exchange membrane has a basis weight of 320 g / m or less. 2 or more and 800g / m 2 The basis weight is, for example, 0.1 m of an anion exchange membrane. 2 The weight of each sample can be measured by cutting a portion of the cellulose acetate sheet into 10 samples and drying at 80° C. in a 0% humidity chamber for 24 hours.

[0137] In one embodiment, the anion exchange membrane is 50 m 2 / g or more, 75m 2 / g or more, 100m 2 / g or more, 150m 2 / g or more, 200m 2 / g or more, 300m 2 / g or more, 400m 2 / g or more, 500m 2 / g or more. In some embodiments, the anion exchange membrane has a specific surface area of ​​1,000 m 2 / g or less, 900m 2 / g or less, 800m 2 / g or less, 750m 2 / g or less, 700m 2 / g or less, 650m 2 / g or less, 600m 2 / g or less, 550m 2 / g or less, 500m 2 / g or less, or even less. Combinations of these ranges are possible. For example, in one embodiment, the anion exchange membrane has a specific surface area of ​​500 g / m 2 or more and 1,000g / m 2 It has the following specific surface area:

[0138] In certain embodiments, the anion exchange membrane includes a compressible edging material. Such a compressible edging material can, in some cases, act as a gasket that can seal the membrane. Having a compressible edging material that can act as a gasket can be useful in some cases where the anion exchange membrane is incorporated into an electrochemical device (e.g., a battery, a fuel cell, etc.). In some cases, the compressible edging material is mechanically compressible. In certain embodiments, the compressible edging material is resistant to heat and / or harsh chemical environments. FIG. 5 shows an exemplary diagram of a non-limiting embodiment in which the anion exchange membrane 100 includes an optional compressible edging material 180.

[0139] In some embodiments, the anion exchange membrane includes a compressible border material along at least a portion of the anion exchange membrane's edge. In some embodiments, the compressible border material penetrates the porous support membrane by at least 1 μm. For example, referring again to FIG. 5 , in some embodiments, the anion exchange membrane 100 includes a silica-containing ceramic 150, a compressible border material 180, and a porous support membrane 130 and compressible border material 180 hidden behind the silica-based ceramic 130, according to some embodiments. In some such cases, the compressible border material 180 penetrates the porous support membrane 130 by at least 1 μm. In some embodiments, the compressible border material is located along all edges of the anion exchange membrane to define a gasket (e.g., as shown in FIG. 5 ). In some embodiments, the compressible border material covers no more than about 50%, no more than 25%, no more than 10%, or no more than 5% of the anion exchange membrane's surface. In some embodiments, the percentage of the external geometric surface area of ​​the anion exchange membrane that is not covered by the compressible edging material is 50% or more, 90% or more, 95% or more, or more. In some embodiments, the percentage of the external geometric surface area of ​​the anion exchange membrane that is not covered by the compressible edging material is 1 cm or more. 2 More than 10cm 2 More than 100cm 2 Over 1,000cm 2 More than and / or up to 1m 2 , up to 2m 2 , up to 5m2 , up to 10m 2 , or greater. The compressible edging material can have a width. For example, compressible edging material 180 in FIG. 5 has width 182. In some embodiments, the compressible edging material is 1 mm or greater in width. In some embodiments, the compressible edging material is 5 mm or greater in width. In some embodiments, the edging portion is 1 cm or greater in width.

[0140] The compressible edging material can be formed on the anion exchange membrane using any suitable method. For example, in some embodiments, the compressible edging material is formed on the porous support membrane before forming the silica-based ceramic coating on and / or within the porous support membrane. In some cases, the compressible edging material is formed on the porous support membrane after forming the silica-based ceramic coating on and / or within the porous support membrane.

[0141] In some embodiments, forming the compressible border material includes impregnating the edge portion of the porous support membrane with a polymeric material, e.g., impregnating one or more or all of the edges or areas near the edges of the porous support membrane with a compressible polymer sufficiently to form a gasket separating the porous support membrane (and ultimately the anion exchange membrane). In some embodiments, the compressible border material is formed using ultrasonic welding, hot pressing, or UV curing. In some embodiments, impregnating the edge portion of the porous support membrane with the compressible polymer includes one or more techniques selected from melting, solution deposition, or in situ reaction.

[0142] In some embodiments, the compressible edging material comprises a polymeric material. In some embodiments, the polymeric material comprises an elastic polymer, such as a thermoplastic elastomeric polymer. Any suitable elastic polymer may be used to form the compressible edging material of the anion exchange membranes disclosed herein. Exemplary polymeric materials that may comprise the compressible edging material include, but are not limited to, silicone, epoxy, polyurethane, acrylic, silicone rubber, poly(styrene-isoprene-styrene), poly(styrene-isobutylene-styrene), polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyetheretherketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, or a combination or derivative thereof.

[0143] As noted above, in some cases, the inventive features associated with the anion exchange membranes and materials described herein can contribute to a number of potentially advantageous performance characteristics.

[0144] In certain embodiments, an anion exchange membrane or material (e.g., anion exchange membrane 100) has a relatively high anion exchange capacity. A relatively high anion exchange capacity is generally associated with good performance characteristics of an anion exchange material. The anion exchange capacity of a material, such as a membrane, can be measured using the following procedure: The anion exchange membrane is immersed in an aqueous solution of sodium chloride (2.0 M) for at least 12 hours, and the sodium chloride solution is exchanged twice with fresh sodium chloride solution during this 12-hour period. After immersion in the sodium chloride solution, the membrane is immersed in deionized water for at least 15 minutes, and the deionized water is exchanged twice with fresh deionized water during this 15-minute period. After immersion in deionized water, the membrane is immersed in an aqueous solution containing 1.0 M sodium nitrate for at least 3 hours, and the 1.0 M sodium nitrate solution is exchanged twice with fresh 1.0 M sodium nitrate solution (or 1.0 M sodium nitrate in deionized water) during this 3-hour period. The anion exchange membrane is removed from the sodium nitrate solution and rinsed with deionized water. The sodium nitrate solution as well as all of the rinse solutions are then combined and titrated with an aqueous solution containing 0.010 M silver nitrate using potassium chromate (0.25 M in solution) as an indicator. The titration is complete when the solution changes from bright yellow to a yellowish brown. An automatic titrator can be used to perform the titration without an indicator such as potassium chromate, for example, instead of using a silver-sensing probe. A series of "blank" sodium nitrate solutions that are not exposed to the anion exchange membrane are used and titrated to determine the baseline chloride ion background for the aqueous solution. The membrane is rinsed with deionized water and dried in an oven overnight. The weight of the membrane is recorded after the drying process. The anion exchange capacity (AEC) is calculated as:

number

[0145] In some embodiments, it has been observed that the anion exchange membranes described herein having a relatively high loading of certain functional groups (e.g., quaternary ammonium groups) contribute, at least in part, to a relatively high anion exchange capacity compared to certain existing anion exchange membranes. Furthermore, it has been observed that the anion exchange capacity of the anion exchange membranes and materials described herein can also depend, at least in part, on the composition of the silicon-containing precursor sol from which the silica-based ceramic of the anion exchange membrane is derived (e.g., water-to-silicon ratio, acid strength, ratio of silicon-containing precursors such as TEOS and TMAPS).

[0146] In some embodiments, the anion exchange membrane or material has an anion exchange capacity of 0.01 milliequivalents per gram (meq / g) or greater. In some embodiments, the anion exchange membrane or material has an anion exchange capacity of 0.1 meq / g or greater, 0.2 meq / g or greater, 0.3 meq / g or greater, 0.5 meq / g or greater, 0.7 meq / g or greater, 1 meq / g or greater, 1.2 meq / g or greater, 1.5 meq / g or greater, 1.7 meq / g or greater, or greater. In some embodiments, the anion exchange membrane or material has an anion exchange capacity of 2.5 meq / g or less, 2.2 meq / g or less, 2 meq / g, 1.8 meq / g or less, 1.5 meq / g or less, 1.2 meq / g or less, 1 meq / g or less, 0.7 meq / g or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane or material has an anion exchange capacity of 0.01 meq / g or more and 2.5 meq / g or less, 0.1 meq / g or more and 2.5 meq / g or less, 0.5 meq / g or more and 2.5 meq / g or less, or 1 meq / g or more and 2.5 meq / g or less. In some embodiments, the anion exchange membrane or material has a relatively high anion exchange capacity while having a relatively high amount of Si present in the silica-based ceramic of the anion exchange membrane. For example, in certain embodiments, the anion exchange membrane has an anion exchange capacity of 0.01 meq / g or more, 0.1 meq / g or more, 0.2 meq / g or more, 0.3 meq / g or more, 0.5 meq / g or more, 0.7 meq / g or more, 1 meq / g or more, and / or at most 1.2 meq / g, at most 1.5 meq / g, at most 1.8 meq / g, or at most 2 meq / g, while having Si present in the silica-based ceramic in an amount of at least 6 wt%, at least 10 wt%, at least 12 wt%, at least 15 wt%, at least 17 wt%, at least 20 wt%, and / or at most 24 wt%, at most 26 wt%, at most 28 wt%, at most 30 wt%, at most 40 wt%, at most 47 wt%, at most 60 wt%, or more.

[0147] In certain embodiments, the anion exchange membrane or material undergoes a relatively small amount of dimensional swelling (in the form of linear expansion) according to the dimensional swelling test described herein. As discussed above, having a relatively small amount of dimensional swelling can be advantageous for an anion exchange membrane or material in some cases. It has been observed that the anion exchange membranes and materials described herein (some of which include silica-based ceramics) can undergo relatively less dimensional swelling (e.g., linear expansion) than certain existing anion exchange membranes or materials, such as those primarily containing polymeric components such as hydrocarbon or fluorocarbon polymers. Without wishing to be bound by any particular theory, it is believed that linear expansion can occur when the pore size or structure of the membrane changes (e.g., swelling, deswelling) based on the environment of the anion exchange membrane (e.g., temperature, humidity, salinity). When the anion exchange membrane is incorporated into a device, such as an electrochemical device (e.g., an electrochemical stack), where the edges of the membrane are fixed in place, swelling / deswelling can result in mechanical stresses that can cause membrane failure. Having a relatively low linear expansion can also facilitate positioning the membrane (e.g., by creating alignment holes in the membrane) when positioning the membrane in a device (e.g., a stack) during assembly. However, in certain embodiments, it is beneficial to have a certain amount of linear expansion (e.g., due to swelling) to allow for percolation of hydrated regions and beneficial performance characteristics (e.g., anion exchange capacity, chloride ion conductivity). The linear expansion of an anion exchange membrane can be measured using the following dimensional swelling test. The dimensional swelling test is performed using a modified version of ASTM D756 and ASTM D570. Membrane samples are cut into 50 mm x 50 mm squares and conditioned in a room maintained at 23°C and 50% relative humidity for 48 hours. After conditioning, the length and width of the membrane sample are measured. The samples are then immersed in either 23°C water or 100°C water for 1 hour. After immersion, the membrane is removed from the water and wiped with a dry cloth. Immediately after the membrane is wiped with a cloth, the length of each side is recorded.The linear expansion of a given dimension (e.g., length or width) is determined by dividing the measured length of that dimension by the original 50 mm length after wiping the membrane with a dry cloth, and is reported as a percentage change relative to the original 50 mm length. For example, a membrane 55 mm long measured after immersion and wiping with a cloth has a linear expansion of 10%, while a membrane 60 mm long measured after immersion and wiping with a cloth has a linear expansion of 20%. The linear expansion of an anion exchange membrane is determined by performing the above dimensional swelling test on three identical samples and determining the number average of the three tests.

[0148] In some embodiments, the anion exchange membrane has a relatively low linear expansion, as described above. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of 10% or less, 8% or less, 6% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or less. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of about 0%. In some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of 0% or more, 0.01% or more, or 0.1% or more. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of 0% or more and 5% or less, 0% or more and 2% or less, 0% or more and 1% or less, or 0% or more and 0.5% or less.

[0149] In some embodiments, the anion exchange membrane has a relatively small linear expansion while having a relatively large anion exchange capacity. For example, in some embodiments, the anion exchange membrane has a linear expansion along at least one dimension of 20% or less, 15% or less, 10% or less, 8% or less, 6% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or less, while having an anion exchange capacity of 0.01 meq / g or more, 0.2 meq / g or more, 0.3 meq / g or more, 0.5 meq / g or more, 0.7 meq / g or more, 1 meq / g or more, and / or up to 1.2 meq / g, up to 1.5 meq / g, up to 1.8 meq / g, up to 2 meq / g, up to 2.5 meq / g, or more. Obtaining such a high anion exchange capacity while experiencing such a small amount of dimensional swelling (e.g., linear expansion) when exposed to water may not be possible with certain existing anion exchange membranes or materials.

[0150] In certain embodiments, anion exchange membranes or materials have relatively high anion permselectivity. Anion permselectivity generally refers to the quantitative determination of the degree to which a membrane or material is more permeable to anions than to cations. Selectivity for anions relative to cations can be an important property of anion exchange membranes in certain applications. Herein, anion permselectivity is measured by comparing the permeability of a membrane or material to chloride anions with that of sodium anions. Permselectivity, in this case, is measured using the open circuit voltage method. The open circuit voltage method is well known in the literature and is described, for example, in Sata, T., Properties, Characterization and Microstructure of Ion Exchange Membranes. In Ion Exchange Membranes: Preparation, Characterization, Modification and Application, Sata, T., Ed., The Royal Society of Chemistry: 2004; pp 89-134 and Kingsbury, RS; Flotron, S.; Zhu, S.; Call, DF; Coronell, O., Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity. Environmental Science & Technology 2018, 52(8), 4929-4936, both of which are incorporated herein by reference in their entirety. In the performance of the open circuit voltage method test, the membrane is equilibrated in 0.5M aqueous NaCl solution before testing. The membrane is then installed in a two-compartment cell. One compartment of the cell is filled with 100 mL of 0.5 M NaCl aqueous solution, while the other compartment is filled with 100 mL of 0.1 M NaCl aqueous solution. Each compartment of the two-compartment cell is stirred, and fresh solution is injected through each compartment at a rate of approximately 5 mL / min. AgCl wire electrodes and a multimeter (e.g., Fluke 116 True RMS) are used to make voltage measurements.An AgCl wire electrode is immersed in each compartment, and a multimeter is set to the dc voltage setting. A multimeter probe is connected to each AgCl wire, and a voltage reading is taken from the multimeter. The wires are allowed to equilibrate for 30 minutes before the final membrane potential is recorded. The anion permselectivity is then calculated using the Nernst equation. The offset potential of the AgCl wires is measured in 0.5 M NaCl and 0.1 M NaCl solutions and averaged to represent the reference potential in the final calculation.

[0151] In some embodiments, the anion exchange membrane or material has an anion permselectivity of 65% or greater. In some embodiments, the anion exchange membrane has an anion permselectivity of 70% or greater, 75% or greater, 80% or greater, 85% or greater, 90% or greater, 95% or greater, 97% or greater, 98% or greater, or greater. In some embodiments, the anion exchange membrane has an anion permselectivity of 100% or less, 99% or less, 98% or less, 97% or less, 95% or less, 90% or less, 85% or less, 80% or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has an anion permselectivity of 65% or greater and 100% or less, 85% or greater and 100% or less, 90% or greater and 100% or less, 95% or greater and 100% or less, or 98% or greater and 100% or less.

[0152] In some embodiments, the anion exchange membrane has a relatively high chloride ion (Cl - ) Conductivity (C Cl). Chloride ion conductivity can be a useful metric for evaluating the conductivity of an anion exchange membrane with respect to anions, such as chloride ions. Having a relatively high chloride ion conductivity can be important in certain applications, such as certain electrochemical applications (e.g., electrodialysis applications). For example, a relatively high chloride ion conductivity can promote energy efficiency in electrochemical systems in certain embodiments. It has been observed that the anion exchange membranes described herein can have a relatively high chloride ion conductivity, at least in part, due to the inventive properties of the anion exchange membrane, e.g., a relatively high loading of functional groups (e.g., quaternary ammonium groups). Chloride ion conductivity can also be affected by the pore structure of the silica-based ceramic (e.g., pore size, interpore distance, pore ordering, e.g., fractal aggregates versus others). It has been observed herein that chloride ion conductivity does not necessarily correlate with other properties of the anion exchange membrane or material (e.g., anion exchange capacity), and that the structural and compositional factors that result in a relatively high sodium conductivity can differ from those that affect other properties. For example, if an anion exchange membrane contains functional groups (e.g., sulfonic acid and / or sulfonate groups) localized near the outer surface of the anion exchange membrane, the membrane may have a relatively high anion exchange capacity but low chloride ion conductivity because the functional groups are not distributed throughout the thickness of the membrane. In contrast, an anion exchange membrane with an effective distribution (e.g., a substantially uniform distribution) of functional groups may have both a relatively high anion exchange capacity and a relatively high chloride ion conductivity. Factors that affect such distribution may include the selection of precursor materials (e.g., silicon-containing precursor materials), the ratio of precursor materials (e.g., in a silicon-containing precursor sol), and the selection of a porous support membrane (if present).

[0153] As another example, certain existing anion exchange compositions having a higher amount of functional groups (e.g., sulfonic acid and / or sulfonate groups) generally tend to have a higher linear expansion because the functional groups tend to adsorb water, resulting in swelling. It has been realized herein that it is possible to achieve an anion exchange membrane with a relatively high chloride ion conductivity and a relatively low linear expansion. One way to achieve such a result is by engineering the pore structure of the silica-based ceramic so that the membrane swells upon hydration sufficiently to achieve percolated pores, but not so much that the pores become too large or lack permselectivity while causing significant linear expansion. In certain embodiments, the percolated pores resulting from some swelling of the membrane can promote both a relatively high chloride ion conductivity and a relatively high anion exchange capacity.

[0154] The chloride ion conductivity of an anion exchange membrane can be measured using a four-electrode electrical impedance spectroscopy (EIS) procedure. The four-electrode electrical impedance spectroscopy procedure is described in detail in Galama, AH; Hoog, NA; Yntema, DR, Method for determining ion exchange membrane resistance for electrodialysis systems. Desalination 2016, 380, 1-11, which is incorporated herein by reference in its entirety. The membrane is equilibrated in a 0.5 M NaCl solution before testing. The membrane is then incorporated into a two-compartment cell. Before incorporating the membrane into the two-compartment cell, the two-compartment cell is first assembled and filled with a 0.5 M NaCl solution to measure the background resistance of the cell. The cell is then emptied, reassembled with the membrane, and filled with a 0.5 M NaCl solution, at which point another resistance measurement is taken. Constant current EIS measurements are used. A constant current of 5 mA is applied to the working platinum electrode and swept from 10,000 Hz to 10 Hz, with 15 points measured every decade. An Ag / AgCl reference electrode is used to measure the resulting voltage across the membrane. The resistances of the blank cell and the cell incorporating the membrane are taken from the x-axis intercept of the resulting Nyquist plot, which represents the real component of the impedance; the difference corresponds to the resistance of the membrane. The conductivity is determined by taking the reciprocal of the resistance and normalized to the membrane surface area and thickness to determine chloride ion conductivity.

[0155] In some embodiments, the anion exchange membrane or material has a chloride ion conductivity of 0.00001 S / cm or greater. In some embodiments, the anion exchange membrane or material has a chloride ion conductivity of 0.00005 S / cm or greater, 0.0001 S / cm or greater, 0.0005 S / cm or greater, 0.001 S / cm or greater, 0.005 S / cm or greater, 0.01 S / cm or greater, or greater. In some embodiments, the anion exchange membrane or material has a chloride ion conductivity of 0.3 S / cm or less, 0.2 S / cm or less, 0.1 S / cm or less, 0.05 S / cm or less, 0.02 S / cm or less, 0.01 S / cm or less, 0.005 S / cm or less, 0.001 S / cm or less, 0.0005 S / cm or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the anion exchange membrane or material has a chloride ion conductivity of ≧0.00001 S / cm and ≦0.3 S / cm, ≧0.001 S / cm and ≦0.3 S / cm, or ≧0.01 S / cm and ≦0.3 S / cm.

[0156] In certain embodiments, the anion exchange membrane or material has a relatively high chloride ion conductivity and a relatively high anion exchange capacity. For example, in certain embodiments, the anion exchange membrane has a conductivity of at least 0.00001 S / cm, at least 0.00005 S / cm, at least 0.0001 S / cm, at least 0.0005 S / cm, at least 0.001 S / cm, at least 0.005 S / cm, at least 0.01 S / cm, and / or at most 0.02 S / cm, at most 0.05 S / cm, at most 0.1 S / cm, at most 0.2 S / cm, or at most 0.01 S / cm. and / or an anion exchange capacity of at most 1.2 meq / g, at most 1.5 meq / g, at most 1.8 meq / g, or at most 2 meq / g. Combinations of the above-referenced ranges of chloride ion conductivity and / or anion exchange capacity as described elsewhere herein are also possible.

[0157] In some embodiments, the anion exchange membrane or material has a relatively high chloride ion conductivity and a relatively low linear expansion. For example, in some embodiments, the anion exchange membrane has a chloride ion conductivity of 0.00001 S / cm or more, 0.00005 S / cm or more, 0.0001 S / cm or more, 0.0005 S / cm or more, 0.001 S / cm or more, 0.005 S / cm or more, 0.01 S / cm or more, and / or up to 0.02 S / cm, up to 0.05 S / cm, up to 0.1 S / cm, up to 0.2 S / cm, or up to 0.3 S / cm, while having a linear expansion of 10% or less, 8% or less, 6% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or less. Combinations of the above-referenced ranges and other ranges of chloride ion conductivity and / or linear expansion described elsewhere herein are also possible.

[0158] In some embodiments, the anion exchange membrane has a relatively low permeability to water. The permeability of a membrane generally refers to the flux of water across the membrane due to osmotic pressure. Having a relatively low permeability to water can be beneficial in certain applications, such as when the anion exchange membrane is used for electrochemical applications, such as electrodialysis. Details of exemplary tests for determining the permeability of a membrane are described in Kingsbury, Ryan; Zhu, Shan; Flotron, Sophie; Coronell, Orlando (2018): Microstructure determines water and salt permeation in commercial ion exchange membranes. ChemRxiv. Preprint and in Kingsbury, RS, Zhu, S., Flotron, S., & Coronell, O. (2018). Microstructure determines water and salt permeation in commercial ion-exchange membranes. ACS Applied Materials & Interfaces, 10(46), 39745-39756, each of which is incorporated herein by reference in its entirety. The osmotic water permeability of the membranes described herein can be determined using the following procedure. The membrane is assembled into a two-compartment cell, and the volumetric flow rate of water across the membrane is measured to determine the water flux across the membrane due to osmotic pressure. One compartment of the two-compartment cell is filled with a 2-4 M NaCl aqueous solution prior to testing. To begin the test, the membrane is assembled into the two-compartment cell, and one compartment of the two-compartment cell is filled with a 4 M NaCl aqueous solution, and the other compartment of the two-compartment cell is filled with deionized water. Before recording the volume change, the membranes are left exposed to a concentration gradient between the 2-4 M NaCl solution and the deionized water solution in their respective compartments for at least 1 hour to establish an apparent steady state for the water transport membrane. The cell is then emptied, and fresh 2-4 M NaCl and deionized water are used to completely refill the cell.The cell is sealed with a lid that fits a volumetric syringe with 0.01 mL increments, and the levels of the solutions in the cell are adjusted to be approximately equal at the start of the test. The two compartments of the two-compartment cell are agitated by stirring with a stir bar for the duration of the test. Once the levels are equal, a stopwatch is started and the volume change over time is recorded until a volume change of at least 0.05 mL is observed in each compartment.

[0159] Water permeability (A[Lm -2 .h -1 .bar -1 ]) is the hydraulic flux of water across the membrane (J W [Lm -2 .h -1 ]):

number

number

number

[0160] In one embodiment, the anion exchange membrane has a viscosity of 100 mL / (hr·bar·m 2) or less, 50mL / (hr·bar·m 2 In one embodiment, the anion exchange membrane has a permeability of 45 mL / (hr·bar·m 2 ) or less, 40mL / (hr·bar·m 2 ) or less, 35mL / (hr·bar·m 2 ) or less, 30mL / (hr·bar·m 2 ) or less, 20mL / (hr·bar·m 2 ) or less, 15mL / (hr·bar·m 2 ) or less, 10mL / (hr·bar·m 2 ) or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2mL / (hr bar m 2 ) or less. In some embodiments, the anion exchange membrane has a permeability of 0 mL / (hr·bar·m 2 ) or more, 0.1mL / (hr·bar·m 2 ) or more, 0.2mL / (hr·bar·m 2 ) or more, 0.3mL / (hr·bar·m 2 ) or more, 0.5mL / (hr·bar·m 2 ) or more, 0.8mL / (hr·bar·m 2 ) or more, 1mL / (hr·bar·m 2 ) or more, 1.2mL / (hr·bar·m 2 ) or more, 1.5mL / (hr·bar·m 2 ) or more, 2mL / (hr·bar·m 2 ) or more, 5mL / (hr·bar·m 2 ) or greater. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a permeability of 0 mL / (hr·bar·m 2 ) or more and 100mL / (hr·bar·m 2 ) or less, 0mL / (hr·bar·m 2 ) or more and 50mL / (hr·bar·m 2 ) or less, 0mL / (hr·bar·m 2 ) or more and 10mL / (hr·bar·m 2 ) or less, 0mL / (hr·bar·m 2) or more and 5mL / (hr·bar·m 2 ) or less, or 0 mL / (hr·bar·m 2 ) or more and 2mL / (hr·bar·m 2 ) has the following permeability to water.

[0161] In some embodiments, the anion exchange membrane has a relatively large water absorption rate. As used herein, the water absorption rate of a membrane refers to the amount of water that the membrane can absorb when immersed in water at 100°C. The water absorption rate of a membrane can be measured using the following procedure: The membrane is cut into a 50 mm x 50 mm square and dried in an oven set at a temperature above 105°C for 24 hours. The weight of the membrane is measured after drying. The water absorption rate is then measured by immersing the membrane in boiling water at 100°C for 1 hour. The membrane is then removed from the boiling water bath, and the surface water is wiped off with a dry cloth. The membrane is then weighed immediately after wiping the membrane with the cloth. This procedure is performed separately on three identical membranes, and the number average of the change in the weight of the membrane after immersion in boiling water is used to determine the water absorption rate of the membrane. In certain embodiments, it has been unexpectedly observed that anion exchange membranes described herein (e.g., anion exchange membranes comprising a silica-based ceramic containing covalently bonded functional groups, such as quaternary ammonium groups) are capable of relatively high water absorption while experiencing a relatively small amount of dimensional swelling (e.g., linear expansion) compared to certain existing anion exchange membranes. Water absorption can be expressed as a percentage change in weight relative to the weight of the dried membrane.

[0162] In some embodiments, the anion exchange membrane has a water absorption of 1% or more, 3% or more, 5% or more, 8% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or more. In some embodiments, the anion exchange membrane has a water absorption of 100% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 50% or less, 40% or less, 35% or less, 25% or less, 15% or less, 10% or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a water absorption of 1% or more and 100% or less, 5% or more and 50% or less, or 10% or more and 25% or less.

[0163] In some embodiments, the anion exchange membrane has a relatively high water absorption and a relatively low linear expansion. In some embodiments, the anion exchange membrane has a water absorption of 1% or more, 3% or more, 5% or more, 8% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, or 70% or more, while having a linear expansion of 10% or less, 8% or less, 6% or less, 5% or less, 2% or less, 1% or less, 0.5% or less, or less. Combinations of the above-referenced ranges and other ranges for water absorption and / or linear expansion described elsewhere in this specification are also possible.

[0164] In certain embodiments, the anion exchange membrane has a relatively high mechanical burst pressure. The mechanical burst pressure of a membrane generally refers to the amount of force that can be applied to the membrane before it experiences mechanical failure and rupture. Having a relatively high mechanical burst pressure can be advantageous for an anion exchange membrane in some cases. For example, in certain applications where a solution is flowed through the anion exchange membrane (e.g., redox flow batteries) or hydrostatic or water pressure is applied to the anion exchange membrane (e.g., reverse osmosis or nanofiltration), having sufficient mechanical burst pressure can be important to avoid membrane failure during operation. In certain embodiments, the anion exchange membranes described herein have been observed to have good mechanical properties, such as high mechanical burst pressure, while also having good performance characteristics (e.g., anion exchange capacity, anion permselectivity). In some cases, such a combination of good mechanical properties and good performance characteristics can be achieved by combining a silica-based ceramic (which can provide good anion exchange performance characteristics) with a porous support membrane (which can provide good mechanical performance).

[0165] The mechanical burst pressure of an anion exchange membrane can be determined using the following procedure. The procedure can be used to determine the burst pressure in units of Newtons (N). The procedure is based on a modified version of ASTM D6797. A circular membrane with a diameter of 70 mm is hydrated with water before testing. The membrane is removed from the water, and excess water on the membrane surface is wiped off with a dry cloth. After wiping the membrane with a dry cloth, the membrane is clamped at its center to a fixture equipped with a clamping ring with an inner diameter of 40 mm. A polished steel ball with a diameter of 25 mm is used to apply force to the membrane. The polished steel ball is attached to the moving part of an extension-type constant-speed tensile tester. The tensile tester is started by setting the travel speed to 305 mm / min, and the ball travel is maintained until the membrane ruptures.

[0166] As described above, in some embodiments, the anion exchange membrane has a relatively high mechanical burst pressure, as measured using the procedures described above. In some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 1.5 N, at least 1.7 N, at least 2.0 N, at least 5 N, at least 10 N, at least 25 N, or more. In some embodiments, the anion exchange membrane has a mechanical burst pressure of 1,000 N or less, 900 N or less, 800 N or less, 700 N or less, 600 N or less, 500 N or less, 400 N or less, 250 N or less, 100 N or less, 75 N or less, 50 N or less, 25 N or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 1.5 N and less than 1,000 N, or 1.7 N or more and less than 400 N.

[0167] The mechanical burst pressure of an anion exchange membrane can also be determined in units of pressure. Such units provide a measure independent of the dimensional characteristics (e.g., membrane area) of the anion exchange membrane. The mechanical burst pressure of an anion exchange membrane can be determined in units of pressure using the following procedure. The procedure is based on a modified version of ASTM D3786 using a Cyeeyo 302AQT burst tester. A circular membrane with a diameter of 40 mm is hydrated with water before testing. The membrane is removed from the water, and excess water on the membrane surface is wiped off with a dry cloth. After wiping the membrane with a dry cloth, the membrane is clamped to a fixture with a clamping ring having an inner diameter of 33 mm at the center of the membrane. During the test, the diaphragm of the burst tester below the sample is expanded upward to the point where the specimen bursts. The burst point, indicated as the peak pressure value, can be read from the burst test display. The burst point corresponds to the mechanical burst pressure.

[0168] As described above, in some embodiments, the anion exchange membrane has a relatively high mechanical burst pressure, measured in units of pressure using the procedures described above. In some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 2.0 pounds per square inch (PSI), at least 2.1 PSI, at least 2.5 PSI, at least 3.0 PSI, at least 3.5 PSI, at least 4.0 PSI, at least 5.0 PSI, at least 6.0 PSI, at least 8.0 PSI, at least 10.0 PSI, at least 12.0 PSI, at least 15.0 PSI, at least 20.0 PSI, at least 25.0 PSI, at least 30.0 PSI, at least 40.0 PSI, at least 50.0 PSI, at least 60.0 PSI, at least 75.0 PSI, at least 100.0 PSI, or more. In some embodiments, the anion exchange membrane has a mechanical burst pressure of 1,000 PSI or less, 900 PSI or less, 800 PSI or less, 700 PSI or less, 600 PSI or less, 500 PSI or less, 400 PSI or less, 250 PSI or less, 150 PSI or less, 100 PSI or less, 90 PSI or less, 80 PSI or less, 75 PSI or less, 70 PSI or less, 65 PSI or less, 60 PSI or less, 55 PSI or less, 50 PSI or less, 40 PSI or less, 30 PSI or less, 25 PSI or less, 10 PSI or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the anion exchange membrane has a mechanical burst pressure of at least 2.0 PSI and less than 1,000 PSI, at least 5.0 PSI and less than 400 PSI, or at least 20 PSI and less than 60 PSI.

[0169] In certain embodiments, methods of making anion exchange membranes in the materials described herein are provided. One exemplary method of making anion exchange membranes includes a sol-gel process.

[0170] FIG. 6 is a flow chart illustrating one non-limiting method for making an anion exchange membrane. In some embodiments, a porous support membrane as described herein is provided. For example, FIG. 6 shows porous support membrane 130. In some cases, an optional step of applying a compressible border material to the porous support membrane is performed. For example, as shown in step 1 in FIG. 6, compressible border material 180 is formed on porous support membrane 130.

[0171] In a non-limiting example, any compressible border material may be formed, at least in part, by adding a polymer to the top surface of a porous support membrane such that the polymer penetrates the entire thickness of the porous support membrane and forms a border having a width of at least 1 μm around the edge region of the porous support membrane. Such a compressible border material may, in some cases, act as a gasket that can help seal the anion exchange membrane (e.g., in a cell). The method of forming the compressible border material depends on the composition (e.g., polymeric material) used to form the compressible border material. In some cases, the compressible border material may be applied as a film and / or sheet using heat, solvents, or radiation. In some embodiments, any compressible border material may be applied to the porous support membrane from the liquid phase as a solution or dispersion using any of a variety of known coating techniques (e.g., dipping, spraying, dropping, blade, screen, etc.). In some embodiments, the method of forming the compressible border material may include depositing a precursor material followed by an in situ reaction. For example, in some cases, an in situ reaction occurs in which deposited monomer units react to form a polymer within the porous support membrane. In some embodiments, the percentage of the external geometric surface area of ​​the porous support membrane that is not covered by the compressible edging material is 30% or more, 40% or more, 50% or more, 70% or more, 80% or more, 90% or more, 95% or more, 99% or more, or more. In some embodiments, the area of ​​the external geometric surface area of ​​the porous support membrane that is not covered by the compressible edging material is 1 cm 2 More than 10cm 2 More than 100cm 2 Over 1,000cm 2 More than and / or up to 1m2 , up to 2m 2 , up to 5m 2 10m 2 , or more.

[0172] In some embodiments, a silicon-containing precursor sol is applied to a porous support membrane during fabrication of an anion exchange membrane. For example, referring again to FIG. 6 , in step 2, the silicon-containing precursor sol is applied to the porous support membrane 130 (optionally including a compressible material 180) via solution 270. Exemplary compositions of silicon-containing precursor sols are described herein. In some embodiments, the silicon-containing precursor sol is applied to the porous support membrane such that the silicon-containing precursor sol penetrates the porous support membrane and coats at least a portion of the porous support membrane. In some embodiments, the sol penetrates the interior of the porous support membrane, and in some cases, fills some or all of the porous volume of the porous support membrane. In some embodiments, the silicon-containing precursor sol (e.g., solution 270) can be applied to the porous support membrane using one or more standard coating processes, such as dip coating, spray coating, roll coating, blade coating, screen printing, or blowing with air (e.g., with an air knife). Excess silicon-containing precursor sol can be removed by any suitable method, such as scraping. The porous support membrane can be in any of a variety of orientations (e.g., vertical, horizontal) during the process of applying the silicon-containing precursor sol to the porous support membrane. In certain embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when it is flat and free-standing. In certain embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when it is flat and in contact with another surface. In certain embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when it is curved and free-standing. In certain embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when it is curved and in contact with another surface. As an example, in some cases, the porous support membrane can be arranged to assume a cylindrical or conical shape during application of the silicon-containing precursor sol (e.g., solution 270 in FIG. 6 ). In certain embodiments, the silicon-containing precursor sol can be applied to the porous support membrane when the membrane is held taut in at least one dimension.

[0173] In some embodiments, the silicon-containing precursor sol is a single-phase sol before and / or during the step of applying the silicon-containing precursor sol to the porous support membrane. For example, in embodiments in which the silicon-containing precursor sol contains two or more different types of silicon-based precursors (e.g., both silanes containing functional groups such as sulfonate or sulfonic acid groups and silanes not containing such functional groups), the silicon-containing precursor sol is a homogeneous mixture containing two or more different types of silicon-based precursors. Applying a single-phase sol can, in some cases, enable the formation of a silica-based ceramic coating on the porous support membrane with certain desirable properties, such as a relatively high loading and / or substantially uniform distribution of functional groups (e.g., quaternary ammonium groups) in the coating.

[0174] In some embodiments, the silicon-containing precursor sol (e.g., solution 270 in FIG. 6 ) is aged prior to applying the silicon-containing precursor sol to a porous support membrane. In some embodiments, aging can occur for at least 0 minutes, at least 30 minutes, at least 2 hours, or more, at which point the precursor materials are mixed to form the sol. In some embodiments, aging can occur for up to 1 week, up to 48 hours, up to 24 hours, or less. Combinations of these ranges are possible. For example, in some embodiments, aging can occur for at least 0 minutes and up to 1 week, at least 30 minutes and up to 48 hours, or at least 2 hours and up to 24 hours. In some embodiments, the temperature of the silicon-containing precursor sol during aging is at least 0° C., at least 20° C., at least 30° C., or higher. In some embodiments, the temperature of the silicon-containing precursor sol during aging is 80° C. or lower, 60° C. or lower, 50° C. or lower, or lower. Combinations of these ranges are possible. For example, in some embodiments, the temperature of the silicon-containing precursor sol during aging is at least 0°C and 80°C, at least 20°C and 60°C, or at least 30°C and 50°C. In some cases, the silicon-containing precursor sol is aged in an open atmosphere (e.g., open to ambient air), while in some embodiments, the conversion step is performed in a closed atmosphere (e.g., in an atmosphere fluidly separated from ambient air). Aging in an open atmosphere can allow for at least partial evaporation during aging, which may be desirable in some, but not necessarily all, embodiments. Aging in a closed atmosphere reduces or eliminates evaporation during aging, which may be desirable in some, but not necessarily all, embodiments.

[0175] In some embodiments, a porous support membrane containing at least a portion of the silicon-containing precursor sol is removed from the solution used to apply the silicon-containing precursor sol, followed by a step of converting the silicon-containing precursor sol into a silica-based ceramic. For example, referring now to step 3 in FIG. 6 , the porous support membrane 130, at least a portion of which is coated with at least a portion of the silicon-containing precursor sol from solution 270, is removed from solution 270. The silicon-containing precursor sol coated on and / or within at least a portion of the porous support membrane (e.g., coated membrane 280) is then converted into a silica-based ceramic according to some embodiments. In some embodiments, converting the silicon-containing precursor sol into a silica-based ceramic involves performing hydrolysis and condensation reactions. In some such embodiments, it has been observed in connection with the present disclosure that the hydrolysis and condensation reactions result in the self-assembly of the components of the silicon-containing precursor sol to form a silica-based ceramic (e.g., as an interconnected network structure, which in some cases is nanoporous).

[0176] In some embodiments, the step of converting the silicon-containing precursor sol coating at least a portion of the porous support membrane into a silica-based ceramic (e.g., by hydrolysis and condensation reactions) lasts for at least 1 second, at least 1 minute, at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, or more. In some embodiments, the step of converting the silicon-containing precursor sol coating at least a portion of the porous support membrane into a silica-based ceramic lasts for 2 weeks or less, 1 week or less, 96 hours or less, 48 ​​hours or less, 24 hours or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the conversion step lasts for at least 1 second and 2 weeks or less, at least 2 hours and 48 hours or less, or at least 4 hours and 24 hours or less. The step of converting the silicon-containing precursor sol coating at least a portion of the porous support membrane into a silica-based ceramic (e.g., by hydrolysis and condensation reactions) can be carried out using any of a variety of conditions. In some cases, the conversion step is carried out in an open atmosphere (e.g., open to ambient air), while in some embodiments, the conversion step is carried out in a closed atmosphere (e.g., in an atmosphere fluidly separated from ambient air). In some embodiments, the conversion step is carried out in an atmosphere having at least 0% humidity and at most 100% humidity.

[0177] The step of converting the silicon-containing precursor sol coating at least a portion of the porous support membrane into a silica-based ceramic (e.g., by hydrolysis and condensation reactions) can be carried out at any of a variety of temperatures, depending on the composition of the silicon-containing precursor sol and the desired properties of the anion-exchange membrane. In some embodiments, the conversion step is carried out at room temperature or lower, while in some embodiments, the conversion step is carried out at an elevated temperature. In some such cases, the coated porous support membrane is held in a dryer (e.g., an oven) during the conversion step. For example, FIG. 6 shows an exemplary coated porous support 20 optionally held in a dryer 24 during at least a portion of step 3, according to some embodiments. In some embodiments, the conversion step is carried out on a coated porous support membrane held in an environment having a temperature of 0° C. or higher, 20° C. or higher, or higher. In some embodiments, the conversion step is carried out on a coated porous support membrane held in an environment having a temperature of 150° C. or lower, 80° C. or lower, 60° C. or lower, or lower. Combinations of these ranges are possible. For example, in some embodiments, the conversion step is carried out on a coated porous support membrane that is maintained in an environment having a temperature of 0° C. or higher and 150° C. or lower, 0° C. or higher and 80° C. or lower, or 20° C. or higher and 60° C. or lower. The temperature conditions under which the conversion step (e.g., hydrolysis and condensation of a silicon-containing precursor sol to form a silica-based ceramic) is carried out can be relatively low compared to certain existing techniques for forming ceramics, such as high-temperature sintering and calcination. In some cases, the use of relatively low temperatures to form a silica-based ceramic allows for reduced costs and resources required to fabricate the anion-exchange membrane compared to certain existing techniques.

[0178] In some embodiments, the converting step can be performed with the coated porous support membrane disposed on or in contact with a surface. For example, in some embodiments, the converting step can be performed with the coated porous support membrane disposed on a relatively flat surface, or a relatively flat and porous surface. However, it should be understood that the coated porous support membrane need not be disposed on or in contact with a surface during the converting step. In some embodiments, the coated porous support membrane is disposed in a horizontal orientation relative to the surface (e.g., horizontal orientation relative to the surface of the oven), while in some embodiments, the coated porous support membrane is disposed in a vertical orientation relative to the surface (e.g., vertical orientation relative to the surface of the oven).

[0179] In some embodiments, the conversion step can be optionally terminated to complete step 3. For example, in some embodiments, the reactions occurring during the conversion step (e.g., hydrolysis and condensation reactions) can be quenched by applying an aqueous solution. The aqueous solution can be applied using standard coating processes, such as dipping, spraying, blade, screen printing, etc. For example, in some embodiments, quenching the reaction includes contacting the converted coated porous support membrane with an aqueous solution (e.g., by applying the aqueous solution to the converted coated porous support membrane, submerging the coated porous support membrane in the aqueous solution, etc.). In some embodiments, the aqueous solution used to quench the reaction has a pH of -1 or greater, 0 or greater, 1 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, 6 or greater, 7 or greater, 8 or greater, 9 or greater, 10 or greater, or greater. In some embodiments, the aqueous solution used to quench the reaction has a pH of 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the aqueous solution used to quench the reaction has a pH of -1 or greater and 14 or less, -1 or greater and 7 or less, or 5 or greater and 7 or less.

[0180] In some cases, it is desirable to remove excess silica-based ceramic in the anion exchange membrane (e.g., to reduce or eliminate surface excess). The excess silica-based ceramic can be removed using any of a variety of suitable methods. Exemplary methods include, but are not limited to, mechanical squeegee removal, air knife removal, and / or heating (e.g., to high temperatures).

[0181] In some embodiments, the method for fabricating an anion exchange membrane described herein is completed after step 3 above. For example, in some embodiments, the membrane 282 produced after step 3 is a fully fabricated anion exchange membrane (e.g., the anion exchange membrane 150 described herein). In some cases, steps of the above method may be repeated. For example, in some embodiments, steps 2 and 3 of the fabrication method may be repeated. Repeating steps 2 and 3 may, in some cases, result in increased coating of the silica-based ceramic on and / or of the porous support membrane. For example, repeating steps 2 and 3 may allow the silicon-containing precursor sol to penetrate regions of the porous support membrane that were not penetrated by the silicon-containing precursor sol during the operation prior to step 2. Such repetition of steps 2 and 3 may, in some cases, result in up to 100% filling of the porous support membrane with the silica-based ceramic. However, it should be understood that repeating steps 2 and 3 above too many times may, in some cases, cause an increase in the surface excess of the silica-based ceramic in the porous support membrane. In other words, in some cases, a layer of silica-based ceramic having too great a thickness may form on the outer surface of the anion exchange membrane, which may, in some cases, be detrimental to the performance of the anion exchange membrane in certain applications. In some cases, it has been observed that performing steps 2 and 3 above a total of 1 to 3 times can result in an anion exchange membrane with beneficial performance characteristics. In some cases, it has been observed that performing steps 2 and 3 above a total of 1 to 6 times (e.g., 4 to 6 times) can result in an anion exchange membrane with beneficial performance characteristics.

[0182] As described above, in certain embodiments, a fully fabricated anion exchange membrane can be prepared after completion of step 3, described above and illustrated in FIG. 6 . For example, in certain embodiments in which the silicon-containing precursor sol includes components containing a functional group desired in the finished anion exchange membrane (e.g., a silane containing a quaternary ammonium group), that functional group can be present in the anion exchange membrane produced after step 3, thereby producing an anion exchange membrane suitable for a particular application without further modification after completion of step 3. As one non-limiting example, in certain embodiments in which the silicon-containing precursor sol includes tetraalkyl orthosilicate (e.g., TEOS) and trialkoxysilylalkyl-N,N,N-trialkylammonium (e.g., trimethoxysilylpropyl-N,N,N-trimethylammonium, TMAPS) as precursors, further modification of the anion exchange membrane may not be necessary after completion of step 3 because, at least at this stage, the anion exchange membrane contains quaternary ammonium groups.

[0183] However, in certain embodiments, one or more additional steps may be performed after step 3 of the methods described herein. For example, in certain embodiments, the silica-based ceramic-coated porous support membrane does not contain a functional group (e.g., a quaternary ammonium group) that is required to be present in the completed anion-exchange membrane after step 3. For example, in certain embodiments, the silicon-containing precursor sol used to coat the porous support membrane does not contain a component containing the desired functional group. As one non-limiting example, in certain embodiments, the silicon-containing precursor sol includes a tetraalkyl orthosilicate (e.g., TEOS) and a silane containing a moiety containing a leaving group (e.g., a halo group, a tosylate group, a trifluoromethane group) as a precursor. In some such cases, additional chemical reactions may need to be performed to convert the moiety containing the leaving group to the desired quaternary ammonium group (e.g., by nucleophilic substitution). Thus, in some cases, additional chemical reactions may be performed to form the desired functional group.

[0184] In some embodiments, after step 3, an optional step of exposing the coated porous support membrane to water may be performed. For example, as shown in FIG. 6, optional step 4 may be performed in which membrane 282 is contacted with water. Exposing the coated porous support membrane to water after step 3 may, in some embodiments, result in the removal of certain components that may be undesirable in subsequent steps of the fabrication process. For example, in some embodiments, exposing the coated porous support membrane to water may remove acid from the membrane structure. Water may be applied using one or more standard coating processes, such as dipping, spraying, blade, and screen printing.

[0185] In some embodiments, a method for forming an anion exchange membrane includes exposing a porous support membrane coated with a silica-based ceramic, at least some of which contain moieties that include leaving groups, to an amine. As shown in FIG. 6 , in some embodiments, membrane 282 includes a porous support membrane coated with a silica-based ceramic, which contains moieties that include leaving groups, and membrane 282 is exposed to an amine in solution 272 during optional step 5. In some embodiments, the method further includes reacting the amine with the moieties to release the leaving groups and form quaternary ammonium groups covalently bonded to the silica-based ceramic. In some such cases, the steps of exposing the porous support membrane to an amine and reacting the moieties with the amine to form quaternary ammonium groups result in an anion exchange membrane that includes quaternary ammonium groups (e.g., covalently bonded to the silica-based ceramic).

[0186] In some embodiments, the partially silica-based ceramic containing leaving groups contains a relatively high percentage of silicon. For example, in some embodiments, the silica-based ceramic contains 6 wt% or more, 10 wt% or more, 12 wt%, 15 wt% or more, 17 wt% or more, 20 wt% or more, 24 wt% or more, 30 wt% or more, 40 wt% or more, 60 wt% or more, or more. In some embodiments, the silica-based ceramic contains 60 wt% or less, 50 wt% or less, 47 wt% or less, 40 wt% or less, 30 wt% or less, 28 wt% or less, 26 wt% or less, 24 wt% or less, 22 wt% or less, 20 wt% or less, 17 wt% or less, or less. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic contains 6 wt% or more and 60 wt% or less, or 17 wt% or more and 26 wt% or less, of Si.

[0187] The moiety containing a leaving group can be any functional group that can release the leaving group to form a quaternary ammonium group after the nucleophilic substitution step. For example, in certain embodiments, the moiety containing a leaving group is a substituted alkyl group (e.g., a haloalkyl group such as a chloropropyl group).

[0188] The amine can be any amine suitable for reacting with a moiety containing a leaving group to form a quaternary ammonium group. In some embodiments, the amine is a tertiary amine. In some embodiments, the amine is trimethylamine.

[0189] Exposing a porous support membrane coated with a silica-based ceramic containing a moiety containing a leaving group to an amine agent can include applying the amine to the coated membrane in any of a variety of suitable ways. For example, as described above, in some embodiments, the exposing step includes exposing the coated porous support membrane to a solution containing an amine (e.g., solution 272 in FIG. 6). The amine can be applied to the coated porous support membrane using standard coating processes, such as dip coating, spray coating, roll coating, blade coating, or screen printing, in some cases. In some embodiments, the amine (e.g., trimethylamine) can be applied to the coated porous support membrane by applying (e.g., by dipping) a solution containing at least 1 vol.%, at least 5 vol.%, at least 10 vol.%, at least 15 vol.%, at least 20 vol.%, or more vol.% of the amine (e.g., triethylamine). In some embodiments, the amine (e.g., trimethylamine) may be applied to the coated porous support membrane by applying (e.g., by dipping) a solution containing 50% by volume or less, 40% by volume or less, 30% by volume or less, 25% by volume or less, 20% by volume or less, 15% by volume or less, 10% by volume or less, or less than or equal to 50% by volume of the amine (e.g., trimethylamine). Combinations of these ranges are possible. For example, in some embodiments, the amine may be applied to the coated porous support membrane by applying a solution containing 1% by volume or more and 50% by volume or less, 10% by volume or more and 50% by volume or more, or 20% by volume or more and 50% by volume of the amine (e.g., trimethylamine).

[0190] In some embodiments, the step of reacting the moiety containing a leaving group with an amine to form a quaternary ammonium group is carried out using a solution containing the amine maintained at a suitable temperature. For example, in some embodiments, the amine-containing solution used in the reaction has a temperature of 0° C. or higher, 20° C. or higher, or higher. In some embodiments, the amine-containing solution used in the reaction has a temperature of 100° C. or lower, 60° C. or lower, 50° C. or lower, or lower. Combinations of these ranges are possible. For example, in some embodiments, the amine-containing solution used in the reaction has a temperature of 0° C. or higher and 100° C. or lower, 0° C. or higher and 60° C. or higher, or 20° C. or higher and 50° C. or lower. The duration of the oxidation reaction to convert the moiety containing a leaving group to a quaternary ammonium group can depend on the reaction rate and the concentration of leaving groups (e.g., halo groups, such as chloro groups) on or in the coated porous support, including, for example, silica-based ceramic. In some cases, the reaction can continue for at least 1 minute, at least 30 minutes, at least 1 hour, or longer. In some cases, the reaction may continue for up to 1 week, up to 48 hours, up to 24 hours, or less. Combinations of these ranges are possible. For example, in some embodiments, the reaction may continue for at least 1 minute and up to 1 week, at least 30 minutes and up to 48 hours, or at least 1 hour and up to 24 hours.

[0191] In some embodiments, an optional drying step may be performed on the anion exchange membrane after the reaction of the amine and leaving group-containing moieties to form quaternary ammonium groups. Figure 6 illustrates optional step 6 according to some embodiments, in which the reacted membrane 284 containing quaternary ammonium groups is dried by being held in optional dryer 26. However, it should be understood that in some embodiments, the drying step may be performed without holding the reacted anion exchange membrane in a dryer. In some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups continues for at least 1 second, at least 1 minute, at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, or more. In some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups continues for up to 24 hours, up to 2 days, up to 1 week, up to 2 weeks, or more. Combinations of these ranges are possible. For example, in some embodiments, the step of drying the reacted anion exchange membrane containing quaternary ammonium groups lasts for at least 1 second and up to 2 weeks, at least 2 hours and up to 2 days, or at least 4 hours and up to 24 hours. The step of drying the reacted anion exchange membrane containing quaternary ammonium groups can be carried out under any of a variety of conditions. In some cases, the drying step is carried out in an open atmosphere (e.g., open to ambient air), while in some embodiments, the drying step is carried out in a closed atmosphere (e.g., in an atmosphere fluidly separated from ambient air). In some embodiments, the drying step is carried out in an atmosphere having a humidity of at least 0% and a humidity of at most 100%.

[0192] The step of drying the reacted anion exchange membrane containing quaternary ammonium groups can be carried out at any of a variety of temperatures. In some embodiments, the drying step is carried out at room temperature or lower, while in some embodiments, the drying step is carried out at an elevated temperature. In some embodiments, the drying step is carried out on the reacted anion exchange membrane held in an environment having a temperature of 0° C. or higher, 20° C. or higher, or higher. In some embodiments, the drying step is carried out on the coated porous support membrane held in an environment having a temperature of 150° C. or lower, 80° C. or lower, 60° C. or lower, or lower. Combinations of these ranges are possible. For example, in some embodiments, the drying step is carried out on the reacted anion exchange membrane held in an environment having a temperature of 0° C. or higher and 150° C. or lower, 0° C. or higher and 80° C. or lower, or 20° C. or higher and 60° C. or lower. In some cases, the resulting anion exchange membrane after the reaction step and / or optional drying step may be suitable for use in any of a variety of applications.

[0193] In some embodiments, the anion exchange material described herein is not in the form of a membrane. For example, in some embodiments, the anion exchange material may include a silica-based ceramic comprising quaternary ammonium groups covalently bonded to the silica-based ceramic described herein, but is not in the form of a membrane. In some such cases, the anion exchange material includes a silica-based ceramic described herein, but does not necessarily include a porous support membrane (e.g., coated on and / or within the silica-based ceramic). One non-limiting example of an anion exchange material not in the form of a membrane is an ion exchange resin. In some embodiments, the anion exchange material is in the form of beads (e.g., anion exchange beads comprising the silica-based ceramic described herein), for example, formed using an emulsion method. As a non-limiting example, FIG. 7 shows a schematic diagram of an anion exchange material 300 comprising a silica-based ceramic 150, according to some embodiments, where the anion exchange material 300 is in the form of beads. In some cases, the silica-based ceramic 150 comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, according to some embodiments, as shown in FIG. 7.

[0194] In some embodiments, the anion exchange material (e.g., a resin) is in the form of a plurality of particles (e.g., a powder) comprising functional groups (e.g., a silica-based ceramic comprising quaternary ammonium groups). In some embodiments, the anion exchange material in the form of particles (e.g., a powder) is formed by mechanically breaking down the silica-based ceramic described herein (e.g., by any suitable technique known in the art, such as milling). The anion exchange material particles can be packed into an ion exchange column and used for any of a variety of applications. In some embodiments, the anion exchange material is in the form of a plurality of particles (e.g., a powder) having an average maximum cross-sectional dimension of 1 μm or more, 2 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 75 μm or more, 100 μm or more, 200 μm or more, 500 μm or more, 1 mm or more, or more. In certain embodiments, the anion exchange material is in the form of a plurality of particles (e.g., a powder) having an average maximum cross-sectional dimension of 10 mm or less, 5 mm or less, 2 mm or less, 1 mm or less, 500 μm or less, 200 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 25 μm or less, or less. Combinations of these ranges are possible. For example, in certain embodiments, the anion exchange material is in the form of a plurality of particles (e.g., a powder) having an average maximum cross-sectional dimension of 1 μm or more and 10 mm or less.

[0195] In some embodiments, an anion exchange material (e.g., beads, particles) is provided that includes a silica-based ceramic that includes quaternary ammonium groups covalently bonded to the silica-based ceramic, where the silica-based ceramic includes a relatively high amount of Si in the silica-based ceramic, as described above. In some embodiments, the silica-based ceramic of the anion exchange material (e.g., beads) includes relatively small pores (e.g., pores having a number average pore diameter of 10 nm or less), as described above. In some embodiments, the anion exchange material (e.g., in the form of beads) has a relatively high anion exchange capacity (e.g., greater than 0.01 meq / g of anion exchange membrane).

[0196] In some embodiments, anion exchange materials not in the form of a membrane can be prepared by reacting a silica-based ceramic containing moieties containing leaving groups with an amine, where the silica-based ceramic is not part of the membrane. For example, in some embodiments, anion exchange membranes containing silica-based ceramic in the form of a resin (e.g., containing a plurality of particles or beads) and containing quaternary ammonium groups can be made using reaction steps similar to those described above for anion exchange membranes. For example, some embodiments include exposing a resin containing a silica-based ceramic containing moieties containing leaving groups (e.g., substituted alkyl groups containing halo groups) to an amine (e.g., triethylamine). In some embodiments, the method further includes releasing the leaving groups to form quaternary ammonium groups.

[0197] In some embodiments, the resin silica-based ceramic contains 6% or more, 10% or more, 12% or more, 15% or more, 17% or more, 20% or more, 24% or more, 30% or more, 40% or more, 60% or more, or more, by weight of Si in the silica-based ceramic. In some embodiments, the resin silica-based ceramic contains 60% or less, 50% or less, 47% or less, 40% or less, 30% or less, 28% or less, 26% or less, 24% or less, 22% or less, 20% or less, 17% or less, or less, by weight of Si in the resin silica-based ceramic. Combinations of these ranges are possible. For example, in some embodiments, the silica-based ceramic contains 6% or more and 60% or less, or 17% or more and 26% or less, by weight of Si in the resin silica-based ceramic. In some embodiments, the silica-based ceramic of the resin containing Si in an amount according to the weight percentage ranges above is a resin containing a leaving group as described herein.

[0198] The anion exchange membranes and materials described herein can be used in any of a variety of applications. For example, in certain embodiments, the anion exchange membranes described herein are used in electrochemical applications. In some cases, electrochemical applications involve applying a current or voltage, for example, to achieve separation of charged ionic species. Using an anion exchange membrane in an electrochemical application can include contacting the anion exchange membrane with an electrolyte. In certain embodiments, using an anion exchange membrane in an electrochemical application can include passing a current through electrodes in electrical communication with the electrolyte. For example, in certain embodiments, the anion exchange membrane is incorporated into an electrochemical device (e.g., a battery, a fuel cell, an electrolysis device, etc.). In some such embodiments, the electrochemical device includes an electrolyte (e.g., a fluid (liquid) electrolyte or a solid electrolyte) in contact with the anion exchange membrane and electrodes in electrical communication with the electrolyte. In certain embodiments, the electrochemical device includes one or more gases (e.g., in contact with the anion exchange membrane) during at least a portion of the charge and / or discharge process (e.g., a fuel cell). Examples of such gases include, but are not limited to, oxygen gas (O), hydrogen gas (H), carbon dioxide (CO), methane (CH), and combinations thereof. In some cases, an electric current is passed through the electrodes (e.g., during the electrochemical reaction) during operation of the electrochemical device (e.g., a charge or discharge process). In some embodiments in which an anion exchange membrane is incorporated into the electrochemical device, the anion exchange membrane is paired with an anion exchange membrane. In some cases, the anion exchange membrane may be packed into a cell, and multiple such cells may be packed into a stack containing two or more anion exchange membranes.Non-limiting examples of electrochemical applications of anion exchange membranes include electrodialysis, batteries (e.g., redox flow batteries), fuel cells, commodity chemical manufacturing (e.g., chlor-alkali production), electrolysis, desalination, wastewater treatment, chromatography, electrodeionization, desalination (e.g., enhanced oil recovery (EOR) desalination, organic wastewater desalination), pollutant chemical removal from wastewater (e.g., ammonia removal from wastewater), water treatment (e.g., mine runoff and mineral processing), food and beverage manufacturing, dairy / whey refining, wine stabilization, biological purification, biochemical manufacturing, coating (e.g., electrodeposition coating), desalination processes, ultrapure water production, plating solution recovery, amine recovery, acid recovery processes, caustic recovery processes, and acid removal processes (e.g., tartaric acid, malic acid, citric acid removal). It should be understood that in some cases, anion exchange membranes can be used in separation applications other than those involving the application of an electric field. For example, in certain embodiments, anion exchange membranes are used in dialysis techniques. One non-limiting example is diffusion dialysis (DD), which can be used in acid recovery processes (e.g., using a concentration gradient to selectively transport anions).

[0199] In certain embodiments, the anion exchange membranes described herein are used as adsorbent materials. For example, in certain embodiments, the anion exchange membranes are incorporated into adsorption devices. In some such embodiments, the anion exchange membranes are used as adsorbent materials to remove liquids from gas streams. In some cases, the anion exchange membranes are used as adsorbent materials to remove dissolved ions from liquid streams (e.g., in an ion exchange process). In certain embodiments, using the anion exchange membrane as an adsorbent material includes flowing a fluid through the anion exchange membrane. In some such embodiments, using the anion exchange membrane as an adsorbent material further includes adsorbing components of the fluid flowing through the anion exchange membrane (e.g., the liquid in the case of removing liquids from a gas stream, or the ions in the case of removing ions from a liquid stream). Non-limiting examples of the use of the anion exchange membranes described herein as adsorbent materials include the use of the anion exchange membranes in pervaporator systems, dehumidifier systems, and / or desiccant or climate control systems.

[0200] In certain embodiments, the anion exchange membranes described herein are used in separation applications. In certain such embodiments, the anion exchange membranes are used in separation applications that involve applying transmembrane pressure to the anion exchange membrane. Non-limiting examples of separation applications in which anion exchange membranes are used by applying transmembrane pressure to the anion exchange membrane include reverse osmosis, microfiltration (e.g., organic solvent microfiltration, aqueous solvent microfiltration), nanofiltration (e.g., organic solvent nanofiltration, aqueous solvent nanofiltration), and ultrafiltration applications. For example, in certain embodiments, the anion exchange membrane is incorporated into a reverse osmosis device, a filtration device, or an ultrafiltration device. Applying transmembrane pressure to the anion exchange membrane may, in some cases, involve contacting the anion exchange membrane with a liquid (e.g., a liquid solution) and applying hydrostatic or water pressure to the liquid such that transmembrane pressure is applied to the anion exchange membrane. In certain such embodiments, at least a portion of the liquid may pass through the anion exchange membrane (e.g., from a first side of the anion exchange membrane to a second side of the anion exchange membrane as permeate).

[0201] As noted above, in certain embodiments, anion exchange materials not in the form of membranes are also described herein (e.g., in the form of a resin comprising a plurality of silica-based ceramic particles or beads). Anion exchange materials, which may comprise silica-based ceramics comprising functional groups as described herein, can be used in any of a variety of applications. For example, in certain embodiments, resins comprising the anion exchange materials described herein are packed into ion exchange columns. In certain such embodiments, ion exchange columns comprising the anion exchange materials can be used in waste treatment (e.g., nuclear waste treatment) and purification processes, such as ultrapure water production or protein and biologic purification.

[0202] Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of the present invention, chemical elements are identified according to the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed., inside cover, and specific functional groups are generally defined as described therein. Furthermore, general principles of organic chemistry, as well as specific functional groups and reactivities, are described in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito: 1999, the entire contents of which are incorporated herein by reference.

[0203] As used herein, the term "aliphatic" refers to alkyl, alkenyl, alkynyl, and carbocyclic groups. Similarly, the term "heteroaliphatic" refers to heteroalkyl, heteroalkenyl, heteroalkynyl, and heterocyclic groups.

[0204] The term "alkyl" is given its ordinary meaning in the art and refers to the radical of a saturated aliphatic group, including a straight-chain alkyl group, a branched-chain alkyl group, a cycloalkyl (alicyclic) group, an alkyl-substituted cycloalkyl group, and a cycloalkyl-substituted alkyl group. In some cases, the alkyl group can be a lower alkyl group, i.e., an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl). In some embodiments, a straight-chain or branched-chain alkyl can have 30 or fewer carbon atoms in its backbone, and in some cases 20 or fewer. In some embodiments, a straight-chain or branched-chain alkyl can have 12 or fewer carbon atoms in its backbone (e.g., C1-C6 for straight-chain). 12 , and for branched chains, C3 to C 12), 6 or fewer, or 4 or fewer. Likewise, cycloalkyls can have from 3-10 carbon atoms in their ring structure, or 5, 6 or 7 carbons in the ring structure. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, t-butyl, cyclobutyl, hexyl, and cyclohexyl.

[0205] The term "alkylene" as used herein refers to a divalent alkyl group. An "alkylene" group is a polymethylene group, i.e., -(CH) z -, where z is a positive integer, for example, 1 to 20, 1 to 10, 1 to 6, 1 to 4, 1 to 3, 1 to 2, or 2 to 3. A substituted alkylene chain is a polymethylene group in which one or more methylene hydrogen atoms have been replaced with a substituent. Suitable substituents include those described herein for substituted aliphatic groups. The alkylene group can be cyclic or acyclic, branched or unbranched, substituted or unsubstituted.

[0206] Generally, the suffix "-ene" is used to represent a divalent group. Thus, any of the terms defined herein can be modified with the suffix "-ene" to represent a divalent form of the moiety. For example, a divalent carbocycle is a "carbocyclylene," a divalent aryl ring is an "arylene," a divalent benzene ring is a "phenylene," a divalent heterocycle is a "heterocyclylene," a divalent heteroaryl ring is a "heteroarylene," a divalent alkyl chain is an "alkylene," a divalent alkenyl chain is an "alkenylene," a divalent alkynyl chain is an "alkynylene," a divalent heteroalkyl chain is a "heteroalkylene," a divalent heteroalkenyl chain is a "heteroalkenylene," a divalent heteroalkynyl chain is a "heteroalkynylene," etc.

[0207] The term "aryl" is given its ordinary meaning in the art and refers to an optionally substituted aromatic carbocyclic group having a single ring (e.g., phenyl), multiple rings (e.g., biphenyl), or multiple fused rings, at least one of which is aromatic (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl). That is, at least one ring may have a conjugated π-electron system, while other adjacent rings may be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, and / or heterocyclyl. Aryl groups may be optionally substituted as described herein. Substituents include, but are not limited to, any of the substituents described above for aliphatic moieties or for other moieties disclosed herein that result in the formation of a stable compound. In some cases, an aryl group is a stable monocyclic or polycyclic unsaturated moiety, preferably having 3 to 14 carbon atoms, each of which may be substituted or unsubstituted. A "carbocyclic aryl group" refers to an aryl group in which the ring atoms in the aromatic ring are carbon atoms. Carbocyclic aryl groups include monocyclic carbocyclic aryl groups and polycyclic or fused compounds (eg, where two or more adjacent ring atoms are common to two adjacent rings), such as naphthyl groups.

[0208] As used herein, the term "arylene" refers to an aryl biradical derived from an aryl group, as defined herein, by the removal of two hydrogen atoms. The arylene group can be substituted or unsubstituted. Arylene group substituents include, but are not limited to, any of the substituents described herein that result in the formation of a stable moiety. Furthermore, an arylene group can be incorporated into an alkylene, alkenylene alkynylene, heteroalkylene, heteroalkenylene, or heteroalkynylene group, as defined herein, as a linker group. The arylene group can be branched or unbranched.

[0209] The terms "halo" and "halogen" as used herein refer to an atom selected from the group consisting of fluorine, chlorine, bromine, and iodine.

[0210] The term "alkoxy," as used herein, refers to an alkyl group, as described above, attached to the parent molecular moiety through an oxygen or sulfur atom. In certain embodiments, the alkyl group contains 1-20 aliphatic carbon atoms. In certain other embodiments, the alkyl group contains 1-10 aliphatic carbon atoms. In still other embodiments, the alkyl, alkenyl, and alkynyl groups employed in the present invention contain 1-8 aliphatic carbon atoms. In still other embodiments, the alkyl group contains 1-6 aliphatic carbon atoms. In still other embodiments, the alkyl group contains 1-4 aliphatic carbon atoms. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, t-butoxy, neopentoxy, and n-hexoxy. Examples of thioalkyl include, but are not limited to, methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, and the like. Alkoxy groups can be cyclic or acyclic, branched or unbranched, substituted or unsubstituted.

[0211] As used herein, a quaternary ammonium group is a quaternary (—N + R x R y R z ) amine groups (e.g., quaternary ammonium salts), where R x , R y , and R z are independently an aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, or heteroaryl moiety, as defined herein. In certain embodiments, the quaternary ammonium group is N + (C 1~4 Contains alkyl)4 salts.

[0212] The terms "heterocyclyl" or "heterocyclic" refer to the radical of a 3- to 14-membered non-aromatic ring system having ring carbon atoms and 1 to 4 ring heteroatoms, where each heteroatom is independently selected from nitrogen, oxygen, and sulfur (a "3- to 14-membered heterocyclyl"). In heterocyclyl groups containing one or more nitrogen atoms, the point of attachment may be at a carbon or nitrogen atom, where valence allows. Heterocyclyl groups may be either monocyclic (a "monocyclic heterocyclyl") or polycyclic (e.g., fused, bridged, or spiro ring systems, e.g., bicyclic (a "bicyclic heterocyclyl") or tricyclic (a "tricyclic heterocyclyl")) and may be saturated or contain one or more carbon-carbon double or triple bonds. Heterocyclyl polycyclic ring systems may contain one or more heteroatoms in one or both rings. "Heterocyclyl" also includes ring systems in which a heterocyclyl ring, as defined above, is fused to one or more carbocyclyl groups, where the point of attachment is on either the carbocyclyl or heterocyclyl ring, or ring systems in which a heterocyclyl ring, as defined above, is fused to one or more aryl or heteroaryl groups, where the point of attachment is on the heterocyclyl ring; in such cases, the number of ring members continues to indicate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each heterocyclyl is independently unsubstituted (an "unsubstituted heterocyclyl") or substituted with one or more substituents (a "substituted heterocyclyl"). In certain embodiments, a heterocyclyl group is an unsubstituted 3- to 14-membered heterocyclyl. In certain embodiments, a heterocyclyl group is a substituted 3- to 14-membered heterocyclyl.

[0213] The term "heteroaryl" refers to the radical of a 5- to 14-membered monocyclic or polycyclic (e.g., bicyclic, tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π-electrons shared in the cyclic array) having ring carbon atoms and 1 to 4 ring heteroatoms provided in the aromatic ring system, where each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5- to 14-membered heteroaryl"). In heteroaryl groups containing one or more nitrogen atoms, the point of attachment may be a carbon or nitrogen atom, as valence permits. Heteroaryl polycyclic ring systems may contain one or more heteroatoms in one or both rings. "Heteroaryl" includes ring systems in which a heteroaryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups, where the point of attachment is on the heteroaryl ring; in such cases, the number of ring members continues to indicate the number of ring members in the heteroaryl ring system. "Heteroaryl" also includes ring systems in which a heteroaryl ring, as defined above, is fused to one or more aryl groups, where the point of attachment is on either the aryl or heteroaryl ring; in such cases, the number of ring members indicates the number of ring members in the fused polycyclic (aryl / heteroaryl) ring system. In polycyclic heteroaryl groups in which one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, etc.), the point of attachment can be on either ring, i.e., on the ring containing the heteroatom (e.g., 2-indolyl) or on the ring without a heteroatom (e.g., 5-indolyl).

[0214] As used herein, "leaving group" (LG) is an art-recognized term that refers to a molecular fragment that leaves along with an electron pair in a heterolytic bond cleavage, where the molecular fragment is an anion or a neutral molecule. As used herein, a leaving group can be an atom or group capable of being pointed by a nucleophile. See, e.g., Smith, March Advanced Organic Chemistry 6th ed. (501-502).

[0215] It will be understood that the groups and / or compounds described herein can be optionally substituted with any number of substituents or functional groups. That is, any of the groups described above can be optionally substituted. As used herein, the term "substituted" is intended to include all permissible substituents of organic compounds, with "permissible" being used in the context of chemical valence rules known to those of ordinary skill in the art. In general, the term "substituted," whether preceded by the term "optionally" or not, refers to the replacement of a hydrogen radical in a given structure with the radical of a specified substituent. When more than one position in any given structure can be substituted with more than one substituent selected from a specified group, the substituents can be the same or different at every position. It will be understood that "substitution" also includes those that result in a stable compound that does not spontaneously undergo transformation, such as, for example, rearrangement, cyclization, or elimination. In some cases, "substitution" can generally refer to the replacement of a hydrogen radical with a substituent described herein. However, as used herein, "substituted" does not encompass the replacement and / or modification of the key functional group by which a molecule is identified, such that, for example, the "substituted" functional group becomes a different functional group upon substitution. For example, a "substituted phenyl group" must still contain a phenyl moiety and, by this definition, cannot be modified by substitution to, for example, a pyridine ring. In a broad aspect, the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and non-aromatic substituents of organic compounds. Exemplary substituents include, for example, those described herein. The permissible substituents can be one or more and can be the same or different for appropriate organic compounds. For purposes of this invention, heteroatoms such as nitrogen can have hydrogen substituents and / or any permissible substituent of organic compounds described herein that satisfies the valence of the heteroatom. Furthermore, the present invention is not intended to be limited in any manner by the permissible substituents of organic compounds. Combinations of substituents and variables envisioned by this invention preferably result in the formation of stable compounds useful for forming imaging agents or imaging agent precursors.The term "stable" as used herein preferably refers to a compound that is stable enough to allow for manufacture and maintains the integrity of the compound for a period of time sufficient to be detected, preferably for a period of time sufficient to be useful for the purposes detailed herein.

[0216] Examples of substituents include, but are not limited to, halogen, azido, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moiety, -CF3, -CN, aryl, aryloxy, perhaloalkoxy, aralkoxy, heteroaryl, heteroaryloxy, heteroarylalkyl, heteroaralkyl, heteroaralkyl, heteroaralkyl, heteroaryloxy, heteroaryl ... Examples of the alkyl group include koxy, azido, amino, halide, alkylthio, oxo, acylalkyl, carboxyester, -carboxamido, acyloxy, aminoalkyl, alkylaminoaryl, alkylaryl, alkylaminoalkyl, alkoxyaryl, arylamino, aralkylamino, alkylsulfonyl, -carboxamidoalkylaryl, -carboxamidoaryl, hydroxyalkyl, haloalkyl, alkylaminoalkylcarboxy-, aminocarboxamidoalkyl-, cyano, alkoxyalkyl, perhaloalkyl, and arylalkyloxyalkyl.

[0217] U.S. Provisional Patent Application No. 62 / 857,227, filed June 4, 2019, and entitled "CERAMIC ANION EXCHANGE MATERIALS," is hereby incorporated by reference in its entirety for all purposes.

[0218] The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention. [Example]

[0219] Example 1 This example demonstrates the performance and structural characteristics of an exemplary anion-exchange membrane. The anion-exchange membrane in this example was fabricated on a nonwoven glass porous support membrane with a polymer edging according to the following procedure. The porous support membrane was fabricated from borosilicate glass fibers without a binder, with an average (mean) pore size of 1 micron. The porous support membrane was initially 254 microns thick prior to sol-gel impregnation. The porous support membrane was first edged with UV-curable silicone to form a disk with a 35 mm outer diameter and an active area inner diameter of 10 mm to 15 mm. An initial mixture containing a 65:35 mass ratio of TEOS:N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride was prepared at 50% in methanol (TMAPS), and 0.3 M hydrochloric acid was added to achieve a final water:silicon molar ratio (R) of 2 and 4. The mixture was stirred and heated to 40°C for 4 hours before being applied to the porous support membrane. The coated porous support membranes were allowed to dry overnight, and for comparison, a set containing a second coat was applied following the same procedure. The membranes were immersed in 0.5 M NaCl prior to characterization, where they exhibited apparent anion permselectivities of 82% to 96% (Figure 8A); chloride ion conductivities of 0.0008 S / cm to 0.001 S / cm (Figure 8B); and a pH of 2.95 mL.m -2 .h -1 .bar -1 ~5.2 mL.m -2 .h -1 .bar -1 The membranes were found to have a permeable water permeability of 0.61 meq / g to 0.95 meq / g (Figure 8C). Similar prepared samples had anion exchange capacities of 0.61 meq / g to 0.95 meq / g. SAXS analysis (based on data and model fits shown in Figure 8D) showed that membranes prepared with a water:silicon molar ratio equal to 4 had an average volume porosity of 9.5%, an average pore radius of 5.1 Å, and an average lognormal polydispersity index of 0.24.

[0220] Example 2 This example demonstrates the structural characteristics of an exemplary anion-exchange membrane. The anion-exchange membrane in this example was fabricated on a nonwoven glass porous support membrane with a polymer edging according to the following procedure. The porous support membrane was fabricated from borosilicate glass fibers without a binder, with an average (mean) pore size of 1 micron. The porous support membrane was initially 254 microns thick prior to sol-gel impregnation. The porous support membrane was first edged with UV-curable silicone to form disks with an outer diameter of 35 mm and an active area inner diameter of 10 mm to 15 mm. Initial mixtures containing different molar ratios of TEOS:N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAPS) (2:1, 4:1, 6:1, 8:1, and 10:1) in 50% methanol were prepared, and 0.3 M hydrochloric acid was added to each to achieve a final water:silicon molar ratio (R) of 2. The mixture was stirred and heated to 40°C for 4 hours before being applied to a porous support membrane. The coated porous support membrane was allowed to dry overnight, and a second coat was applied following the same procedure. SAXS analysis (based on the data shown in Figure 9A and a Teubner-Strey model fit) showed that the membranes had pores with radii ranging from 6 Å to 20 Å and volume porosities ranging from 4% to 22%. As shown in Figures 9B-9C, a 6:1 TEOS:TMAPS ratio resulted in a pore radius of 6.1 Å and a volume porosity of 21%. Figure 9D shows the anion exchange capacity for the same membrane.

[0221] Example 3 This example demonstrates the performance and structural characteristics of exemplary anion-exchange membranes. The anion-exchange membranes in this example were fabricated on nonwoven porous polymer support membranes of two different thicknesses (190 and 210 microns) without polymer edging, following a procedure similar to that described in Example 2, but with a 6:1 molar ratio of TEOS to TMAPS and an R value of 2. The mixture was aged at 40°C for 1 hour, followed by an additional open-aging step at 100°C for 30 minutes before coating onto the porous support. The coated support was dried at room temperature for 2 hours, and the coating procedure was then repeated. This final membrane had four coats before drying overnight. The anion-exchange membranes were immersed in a 0.5 M NaCl solution prior to characterization. The anion-exchange membranes were found to have apparent anion permselectivities of 92–94% (see FIG. 10A) with chloride ion conductivities of 0.0062–0.0079 S / cm (see FIG. 10B). Membranes prepared in a similar manner were found to have an average anion exchange capacity of 1.4 meq / g.

[0222] Figure 11 shows a cross-sectional SEM image of one of the anion-exchange membranes of this example. In Figure 11, the cross section includes the nonwoven porous polymer support membrane, shown as dark polymer fibers occupying the central horizontal region of the cross section. Some of the polymer fibers extend horizontally into the plane of the figure, while others extend perpendicular to the plane of the figure, appearing as circles in the cross section. The cross section includes the nanoporous silica-based ceramic of the anion-exchange membrane as a dense, uniform slab of lighter-contrast material surrounding and within the porous support membrane.

[0223] Example 4 This example demonstrates the performance and structural characteristics of exemplary anion-exchange membranes. The anion-exchange membranes in this example were fabricated on a nonwoven porous glass support membrane with a polymer edging, following a procedure similar to that described in Example 2, but with a 6:1 molar ratio of TEOS to TMAPS, an R value of 2, and two to five coats. The time it took to coat the sol on the sample (15 to 60 minutes) and whether the samples were dried in an open or closed atmosphere were varied to examine performance changes. All samples were immersed in a 0.5 M NaCl solution before characterization. The apparent permselectivity for these samples was found to be between 88% and 100% (see Figure 11A). The chloride ion conductivity was between 0.0009 S / cm and 0.003 S / cm (see Figure 11B).

[0224] 11C shows a cross-sectional SEM image of one of the anion exchange membranes of this example. In FIG. 11C, the cross section includes the nonwoven porous polymer support membrane, shown as dark polymer fibers 401 occupying the central horizontal region of the cross section. Some of the polymer fibers extend horizontally into the plane of the figure, while others extend perpendicular to the plane of the figure, appearing as circles in the cross section. The cross section includes the nanoporous silica-based ceramic of the anion exchange membrane as a dense, uniform slab of lighter-contrast material 402 on and within the porous support membrane.

[0225] While several embodiments of the present invention have been described and illustrated herein, those skilled in the art will readily envision various other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein. Each such variation and / or modification is considered to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the specific application or applications for which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Accordingly, it should be understood that the above-described embodiments are presented by way of example only, and that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described and claimed. The present invention relates to each individual feature, system, article, material, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials and / or methods, if such features, systems, articles, materials and / or methods are not mutually inconsistent, is included within the scope of the present invention.

[0226] The indefinite articles "a" and "an," as used in the specification and claims, unless the context clearly indicates otherwise, should be understood to mean "at least one."

[0227] The term "and / or" as used in the specification and claims should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Unless expressly stated otherwise, other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether related or unrelated to the elements specifically identified. Thus, as a non-limiting example, a reference to "A and / or B," when used with an open-ended term such as "comprising," can refer to, in one embodiment, A but not B (optionally including elements other than B); in another embodiment, B but not A (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements), etc.

[0228] As used in this specification and the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as being inclusive, i.e., including not only at least one of a number or list of elements, but also two or more, and, optionally, further unlisted items. A specifically expressly stated limiting term, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," refers to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein, when preceded by exclusive terms such as "either," "one of," "only one of," or "exactly one of," shall be interpreted simply as indicating exclusive alternatives (i.e., "one or the other, but not both"). When used in the claims, "consisting essentially of" shall have its ordinary meaning as used in the field of patent law.

[0229] As used in this specification and claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but does not necessarily include at least one of every element specifically listed in the list of elements, and does not exclude any combinations of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to the specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B" or, equivalently, "at least one of A and / or B") can refer in one embodiment to at least one, optionally two or more, A, and no B (and optionally including elements other than B); in another embodiment to at least one, optionally two or more, B, and no A (and optionally including elements other than A); in yet another embodiment to at least one, optionally two or more, A, and at least one, optionally two or more, B (and optionally including other elements), etc.

[0230] In the claims, as well as in the foregoing specification, all transitional phrases such as "comprise," "include," "carry," "have," "contain," "accompany," "hold," and the like, are to be understood to be open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

1. a porous support membrane; a silica-based ceramic coating at least a portion of the porous support membrane; wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and the silica-based ceramic has an average pore size of 10 nm or less.

2. a porous support membrane; a silica-based ceramic coating on and / or within the porous support membrane; wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and the anion exchange membrane has a chloride ion conductivity of 0.00001 S / cm or greater.

3. 1. An anion exchange membrane comprising a silica-based ceramic, the anion exchange membrane having a water absorption rate of 10% by weight or more and a linear expansion of 10% or less.

4. a porous support membrane; a silica-based ceramic coating at least a portion of the porous support membrane; wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and 50% or more of the pore volume of the porous support membrane is filled with the silica-based ceramic.

5. a porous support membrane; a silica-based ceramic coating on and / or within the porous support membrane; wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and the anion exchange membrane has an anion exchange capacity of 0.01 meq / g or greater.

6. a porous support membrane; a silica-based ceramic coating at least a portion of the porous support membrane; wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic, and the quaternary ammonium groups are present in the anion exchange membrane in an amount of 0.01 mmol or greater per gram of the anion exchange membrane.

7. Silica-based ceramics containing quaternary ammonium groups covalently bonded to the silica-based ceramic - Patents.com wherein the silica-based ceramic comprises Si in an amount equal to or greater than 6% by weight of the silica-based ceramic; the anion exchange material has an anion exchange capacity of 0.01 meq / g or more; An anion exchange material, wherein the silica-based ceramic has an average pore size of less than 10 nm.

8. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic wherein the anion exchange membrane has an anion exchange capacity of 0.01 meq / g or more.

9. An anion exchange membrane comprising a silica-based ceramic, the anion exchange membrane having an anion exchange capacity of 0.01 meq / g or more and a linear expansion of 10% or less.

10. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic wherein the anion exchange membrane has an anion permselectivity of 65% or more.

11. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic wherein the anion exchange membrane has a chloride ion conductivity of 0.00001 S / cm or more.

12. An anion exchange membrane comprising a silica-based ceramic, the anion exchange membrane having a chloride ion conductivity of 0.00001 S / cm or more and a linear expansion of 10% or less.

13. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic An anion exchange membrane comprising: ２ ) An anion exchange membrane having an osmotic water permeability of:

14. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic wherein the silica-based ceramic contains pores, and the average diameter of the pores in the silica-based ceramic is at least 1.1 times larger when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

15. Silica-based ceramic containing Si in an amount of 6% by weight or more of the silica-based ceramic 1. An anion exchange membrane comprising: When the anion exchange membrane is in a dry state, the silica-based ceramic pores fit a model of a small-angle scattering spectrum with intensity (I) as a function of scattering vector, q, as follows: [Equation 1] In the formula, a, c １ , and c ２ is an adjustable parameter, bck is the background scattering; When the anion exchange membrane is in a hydrated state, the pores of the silica-based ceramic fit a core-shell model of small-angle scattering spectra with intensity (I) as a function of scattering vector, q, as follows: I(q)=P(q)S(q)+bck [Equation 2] In the formula, R ｏ is the radius of the constituent unit (pore), and ρ ｓｏｌｖｅｎｔ is the scattering length density of the silica-based ceramic, and D ｆ is the fractal dimension, ξ is the correlation length, Γ is the standard mathematical gamma function, scale is the volume fraction of the constituent units of the measured silica-based ceramic, and V ｃ is the volume of the core, and V ｓ is the volume of the shell, and ρ ｃ is the scattering length density of the core, and ρ ｓ is the scattering length density of the shell, and ρ ｂｌｏｃｋ is the scattering length density of the pore, and r ｃ is the radius of the core, and r ｓ is the radius of the shell and bck is the background scattering.

16. A method for using an anion exchange membrane according to any one of claims 1 to 6, 8 to 15 and 21 to 113 in an electrochemical application, comprising: contacting the anion exchange membrane with an electrolyte; and passing an electric current through an electrode in electrical communication with said electrolyte; A method comprising:

17. A method for using an anion exchange material according to any one of claims 7 and 21 to 113 in electrochemical applications, comprising the steps of: contacting the anion exchange material with an electrolyte; and passing an electric current through an electrode in electrical communication with said electrolyte; A method comprising:

18. A method for using the anion exchange membrane of any one of claims 1 to 6, 8 to 15, and 21 to 113 as an adsorption material, comprising: passing a fluid through the anion exchange membrane; and adsorbing components of said fluid; A method comprising:

19. A method for using an anion exchange material according to any one of claims 7 and 21 to 113 as an adsorption material, comprising flowing a fluid through the anion exchange material; and adsorbing components of said fluid; A method comprising:

20. 114. A method for using the anion exchange membrane of any one of claims 1 to 6, 8 to 15, and 21 to 113 in a separation application, the method comprising applying a transmembrane pressure to the anion exchange membrane.

21. 21. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 20, further comprising a porous support membrane coated with said silica-based ceramic.

22. 22. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 21, wherein the silica-based ceramic comprises quaternary ammonium groups covalently bonded to the silica-based ceramic.

23. 23. The anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 22, wherein the silica-based ceramic has an average pore size of 10 nm or less.

24. 24. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 23, wherein the quaternary ammonium groups are immediately adjacent to the surface of the porous support membrane.

25. 25. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 24, wherein the quaternary ammonium groups are present in the anion exchange membrane or anion exchange material in an amount of 0.01 mmol per gram of the anion exchange membrane or anion exchange material.

26. 26. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 25, wherein the quaternary ammonium groups are present in the anion exchange membrane or anion exchange material in an amount of 0.1 mmol per gram of the anion exchange membrane or anion exchange material.

27. 27. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 26, wherein the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic, based on the average amount of quaternary ammonium groups across the thickness of the coating.

28. 28. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 27, wherein the quaternary ammonium groups are substantially uniformly distributed within the silica-based ceramic based on a maximum amount of quaternary ammonium groups across the thickness of the coating.

29. 29. The anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 28, wherein the anion exchange membrane or anion exchange material has an anion exchange capacity of 0.01 meq / g or greater.

30. 30. The anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 29, wherein the anion exchange membrane or anion exchange material has an anion exchange capacity of 0.1 meq / g or greater.

31. 31. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 30, wherein the silica-based ceramic comprises Si in an amount of 6% or more by weight of the silica-based ceramic.

32. 32. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 31, wherein the silica-based ceramic comprises Si in an amount equal to or greater than 1.5 mol% of the silica-based ceramic.

33. 33. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 32, wherein the anion exchange membrane has a linear expansion of 10% or less.

34. 34. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 33, wherein the anion exchange membrane has a linear expansion of 5% or less.

35. 35. The anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 34, wherein the anion exchange membrane has an anion permselectivity of 65% or greater.

36. 36. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 35, wherein the anion exchange membrane has a chloride conductivity of 0.00001 S / cm or greater.

37. The anion exchange membrane has a flow rate of 100 mL / (hr·bar·m ２ 37. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 36, having an osmotic water permeability of 0.1% or less.

38. The anion exchange membrane has a flow rate of 50 mL / (hr·bar·m ２ 38. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 37, having an osmotic water permeability of 0.15 to 0.25 mm / s or less.

39. 39. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 38, wherein there is no intervening layer between the silica-based ceramic comprising the quaternary ammonium groups and the porous support membrane.

40. 40. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 39, wherein the silica-based ceramic comprises pores, and the average diameter of the pores in the silica-based ceramic is at least 1.1 times larger when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

41. 41. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 40, wherein the silica-based ceramic comprises pores, and the average diameter of the pores of the silica-based ceramic is no more than five times smaller when the anion exchange membrane is in a hydrated state than when the anion exchange membrane is in a dry state.

42. The silica-based ceramic comprises pores, wherein: When the anion exchange membrane or anion exchange material is in a dry state, the pores of the silica-based ceramic fit a model of a small-angle scattering spectrum with intensity (I) as a function of the scattering vector, q, as follows: [Equation 3] In the formula, a, c １ , and c ２ is an adjustable parameter, bck is the background scattering; When the anion exchange membrane or anion exchange material is in a hydrated state, the pores of the silica-based ceramic fit a core-shell model of small-angle scattering spectra with intensity (I) as a function of scattering vector, q, as follows: I(q)=P(q)S(q)+bck [Equation 4] In the formula, R ｏ is the radius of the constituent unit (pore), and ρ ｓｏｌｖｅｎｔ is the scattering length density of the silica-based ceramic, and D ｆ is the fractal dimension, ξ is the correlation length, Γ is the standard mathematical gamma function, scale is the volume fraction of the constituent units of the measured silica-based ceramic, and V ｃ is the volume of the core, and V ｓ is the volume of the shell, and ρ ｃ is the scattering length density of the core, and ρ ｓ is the scattering length density of the shell, and ρ ｂｌｏｃｋ is the scattering length density of the pore, and r ｃ is the radius of the core, and r ｓ 42. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 41, wherein is the radius of the shell and bck is the background scattering.

43. 43. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 42, wherein the silica-based ceramic forms a monolayer on the porous support membrane.

44. 44. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 43, wherein the quaternary ammonium groups are within 1 μm of the surface of the porous support membrane.

45. 45. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 44, wherein the silica-based ceramic is derived from a sol-gel.

46. 46. ​​The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 45, wherein the silica-based ceramic is derived from the co-condensation of silicon-containing precursors that include moieties that contain ammonium groups or leaving groups.

47. 47. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 46, wherein the silica-based ceramic has a molar ratio of silicon to nitrogen of 1:1 or greater.

48. 48. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 47, wherein the silica-based ceramic has a molar ratio of silicon to nitrogen of 120:1 or less.

49. 49. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 48, wherein the silica-based ceramic has a silicon to carbon molar ratio of 1:100 or greater.

50. 50. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 49, wherein the silica-based ceramic has a silicon to carbon molar ratio of 1:50 or greater.

51. 51. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 50, wherein the silica-based ceramic has a silicon to carbon molar ratio of 3,000:1 or less.

52. 52. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 51, wherein the silica-based ceramic is derived from a mixture containing a nitrogen-containing silane.

53. The silica-based ceramic has structure (IV): 【Chemistry 1】 wherein R １ , R ２ , and R ３ are independently optionally substituted C １～１８ alkoxy and halo, and L is optionally substituted C １～１８ 53. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 52, wherein X is a leaving group selected from alkylene and arylene.

54. The silica-based ceramic has the structure (V): 【Chemistry 2】 wherein A is derived from a mixture comprising a compound having the formula １ is independently selected from hydrogen, methyl, ethyl, propyl, or butyl; n is greater than or equal to 1 and less than or equal to 18; and X is a leaving group.

55. 55. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 54, wherein X is selected from chloro, bromo, iodo, tosyl, and trifluoromethanesulfonyl.

56. 56. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 55, wherein the silica ceramic is derived from a mixture comprising (3-chloropropyl)triethoxysilane.

57. The silica-based ceramic has the structure (VI): 【Transformation 3】 wherein R ４ , R ５ , and R ６ are independently optionally substituted C １～１８ alkoxy and halo, and L is optionally substituted C １～１８ alkylene and arylene; R ７ , R ８ , and R ９ are independently optionally substituted C １～１８ 57. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 56, wherein the anion exchange group is selected from alkyl, cyclyl, and aryl.

58. The silica-based ceramic has the structure (VII): 【Chemistry 4】 wherein A is derived from a mixture comprising a compound having the formula ２ is independently selected from hydrogen, methyl, ethyl, propyl, or butyl; n is greater than or equal to 1 and less than or equal to 18; R １０ , R １１ , and R １２ 58. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 57, wherein is independently selected from methyl, ethyl, propyl, butyl, cyclohexyl, and benzyl.

59. 59. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 58, wherein the silica-based ceramic is derived from a mixture comprising trimethoxysilylpropyl-N,N,N-trimethylammonium.

60. The silica-based ceramic has the structure (VIII): 【Transformation 5】 wherein R １３ are independently hydrogen or optionally substituted C １～１８ 60. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 59, wherein the anion exchange membrane is selected from alkyl.

61. 61. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 60, wherein the silica-based ceramic is derived from a mixture comprising a compound having the structure of tetraethyl orthosilicate.

62. 62. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 61, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII), a compound having structure (IV), and water, in a molar ratio of 1:0.01-20:1-30.

63. 63. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 62, wherein the silica-based ceramic is derived from a mixture comprising a compound having structure (VIII), a compound having structure (VI), and water in a molar ratio of 1:0.01-20:1-30.

64. 64. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 63, wherein the silica-based ceramic has an average pore size of 1 μm or less.

65. 65. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 64, wherein the silica-based ceramic has an average pore size of 2 nm or less.

66. 66. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 65, wherein the silica-based ceramic has an average pore size of 0.25 nm or greater.

67. 67. An anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 66, wherein the anion exchange membrane or material has a volume porosity of 1% or greater.

68. 68. An anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 67, wherein the anion exchange membrane or material has a volume porosity of 70% or less.

69. 69. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 68, wherein the pores of the silica-based ceramic have an aspect ratio of 40:1 or less.

70. 70. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 69, wherein the pores of the silica-based ceramic have an ordered structure.

71. 71. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 70, wherein the pores of the silica-based ceramic are approximately spherical.

72. The pores of the silica-based ceramic are 10 or less ２ 72. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 71, wherein the small-angle scattering spectrum is fitted to a spherical model with a value of / N, where N is the number of small-angle scattering data points across the spherical model fit range.

73. 73. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 72, wherein the silica-based ceramic has a fractal porous structure.

74. 74. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 73, wherein the pores of the silica-based ceramic have a log-normal polydispersity index of pore radius of less than or equal to 0.

8.

75. 75. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 74, wherein the porous support membrane comprises pores having an average pore size of 50 nm or greater in the absence of the silica-based ceramic.

76. 76. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 75, wherein the porous support membrane comprises pores having an average pore size of 50 μm or less in the absence of the silica-based ceramic.

77. 77. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 76, wherein the porous support membrane has a cross-sectional thickness of 3 μm or greater.

78. 78. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 77, wherein the porous support membrane has a cross-sectional thickness of 1,000 μm or less.

79. 79. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 78, wherein the porous support membrane has a volume porosity of 10% or greater.

80. 80. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 79, wherein the porous support membrane has a volume porosity of 99% or less.

81. 81. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 80, wherein the porous support membrane comprises support elements having an average diameter of 10 nm or greater.

82. 82. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 81, wherein the porous support membrane comprises a support element having an average diameter of 50 μm or less.

83. 83. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 82, wherein the support component is selected from a fiber, a yarn, and a wire.

84. 84. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 83, wherein the porous support membrane is in the form of a nonwoven fabric or mesh, a veil, a knitted fabric, a woven fabric or mesh, an open-cell structure, a fibril and node structure, or an open-cell foam.

85. 85. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 84, wherein the porous support membrane comprises a polymeric material.

86. 86. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 85, wherein the polymeric material comprises polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, microfibrillated cellulose, nanofibrillated cellulose, or a combination or derivative thereof.

87. 87. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 86, wherein the porous support membrane comprises a ceramic material.

88. 88. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 87, wherein the ceramic material comprises borosilicate glass, silica, titania, zirconia, alumina, silicon carbide, silicon nitride, boron nitride, lithium silicate, potassium silicate, tin oxide, iron oxide, or a combination thereof.

89. 89. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 88, wherein the porous support membrane comprises a metal and / or a metal alloy.

90. 90. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 89, wherein the metal and / or metal alloy comprises iron or steel.

91. 91. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 90, wherein the porous support membrane comprises one or more amphiphilic molecules on a surface of the support membrane.

92. 92. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 91, wherein the amphiphilic molecule comprises a sodium alkyl sulfate, a dialkyl sulfosuccinate, or an alkyltrimethylammonium halide.

93. 93. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 92, wherein 50% or more of the pore volume of the porous support membrane is filled with the silica-based ceramic.

94. 94. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 93, wherein the anion exchange membrane comprises a edging material comprising a polymeric material.

95. 95. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 94, wherein the anion exchange membrane comprises a rim material comprising silicone, epoxy, polyurethane, acrylic, silicone rubber, poly(styrene-isoprene-styrene), poly(styrene-isobutylene-styrene), polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyamide, polyimide, polyacetonitrile, polyvinyl acetate, polyethylene glycol, polyether ether ketone, polysulfone, polyacrylamide, polydimethylsiloxane, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyphenylene sulfide, polytetrafluoroethylene, cellulose, or a combination or derivative thereof.

96. 96. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 95, wherein the anion exchange membrane or anion exchange material has a water absorption of 1% or more.

97. 97. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 96, wherein the anion exchange membrane has a linear expansion of 0.5% or less.

98. 98. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 97, wherein the anion exchange membrane has a linear expansion of 0.01% or more.

99. 99. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 98, wherein the anion exchange membrane or anion exchange material has an anion permselectivity of 85% or greater.

100. 100. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 99, wherein the porous support membrane has a mechanical burst pressure of 1.5 N or greater.

101. 101. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 100, wherein the porous support membrane has a mechanical burst pressure of 2.0 pounds per square inch (PSI) or greater.

102. 102. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 101, wherein the leaving group is selected from chloro, bromo, iodo, tosyl, and trifluoromethanesulfonyl.

103. 103. The anion exchange membrane, anion exchange material or method of any one of claims 1 to 102, wherein the leaving group is chloro.

104. 104. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 103, wherein the amine is a tertiary amine.

105. 105. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 104, wherein the amine is trimethylamine.

106. 106. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 105, wherein the anion exchange material is in the form of a resin.

107. 107. The anion exchange membrane, anion exchange material or method of any one of claims 1 to 106, wherein the anion exchange material is in the form of a plurality of particles.

108. 108. An anion exchange membrane, anion exchange material or method according to any one of claims 1 to 107, wherein the particles have an average largest cross-sectional dimension of 1 μm or greater.

109. 109. An anion exchange membrane, anion exchange material, or method according to any one of claims 1 to 108, wherein the particles have an average largest cross-sectional dimension of 1 cm or less.

110. 110. The anion exchange membrane, anion exchange material or method of any one of claims 1 to 109, wherein the anion exchange material is in the form of beads.

111. 111. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 110, wherein the anion exchange membrane is incorporated into an electrochemical device.

112. 112. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 111, wherein the anion exchange membrane is incorporated into a reverse osmosis, nanofiltration, or ultrafiltration device.

113. 113. The anion exchange membrane, anion exchange material, or method of any one of claims 1 to 112, wherein the anion exchange membrane is incorporated into an adsorption device.

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