Porous membrane having aromatic fluorinated polymer and method of forming the same

Abstract

This invention provides polymers comprising aromatic fluoropolymers or incorporating fluorine groups into the polymer, which increases the polymer's chemical resistance and thermal stability. The combination of these properties offers potential uses in membrane applications. Porous membranes obtained from the disclosed polymers exhibit improved chemical resistance and stability.

Description

Cross-reference to related applications

[0001] This application claims priority and benefit to U.S. Provisional Patent Application No. 63 / 544,108, filed October 13, 2023. The entire contents of the aforementioned application are incorporated herein by reference. Summary of the Invention

[0002] Porous polymer membranes can be used to remove contaminants from a variety of fluids. Factors for selecting a polymer for a membrane include (but are not limited to) the polymer’s cleanliness (e.g., having minimal oligomer shedding), its chemical compatibility with the specific fluid from which it removes contaminants, and its solubility in a solvent at room temperature, making it suitable for polymer phase separation membrane formation processes such as NIPS (non-solvent-induced phase separation) and VIP (vapor-induced phase separation).

[0003] Polymers currently used in porous polymer membranes (which can be used in polymer phase separation membrane formation processes) include, but are not limited to, polysulfone, polyethersulfone, polyarylsulfone, polyvinylidene fluoride, cellulose polymers, polyacrylonitrile, and nylon. However, polymer membranes prepared from these polymers have severe chemical compatibility limitations when used in acidic (low pH), alkaline (high pH), and oxidizing environments. When exposed to these environments or used for removing contaminants from acidic, alkaline, or oxidizing fluids, these membranes can dissolve, degrade, rupture, or their polymer chains can break and oligomers can detach, thus introducing various contaminants into the fluid. This makes them unsuitable or limits their service life.

[0004] Therefore, there is a need for polymers that are not subject to these limitations but are soluble in common solvents and can be processed into porous membranes using polymer phase separation processes such as NIPS and VIPS.

[0005] The polymers disclosed in this article (also described as aromatic fluoropolymers (AFP)) address this need.

[0006] The membrane disclosed herein is prepared from a polymer containing an aromatic fluoropolymer or a polymer incorporating fluorine groups, which can increase the chemical resistance and thermal stability of the polymer, and thus increase the chemical resistance and thermal stability of the membrane containing the polymer. This combination of properties provides potential applications in membrane applications.

[0007] In some embodiments, the porous membranes disclosed herein comprise:

[0008] Polymer, said polymer comprising one or more monomer units having the formula according to formula (I):

[0009]

[0010] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0011] In some embodiments, the porous membranes disclosed herein comprise an aromatic fluoropolymer, wherein the membrane has an initial bubble point in the range of 1 to 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C and an IPA flow time in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml when measured at 14.2 psi.

[0012] In some embodiments, the porous membrane disclosed herein comprises an aromatic fluoropolymer, wherein the initial bubble point of the membrane does not change by more than 20% when the initial bubble point of the membrane is measured before and three days after immersion in 96% sulfuric acid, wherein the initial bubble point of the membrane is measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0013] In some embodiments, a method disclosed herein includes: preparing a porous membrane using a polymer comprising one or more monomer units having the formula (I):

[0014]

[0015] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl. Attached Figure Description

[0017] Some embodiments of this disclosure are described herein by way of example only, with reference to the accompanying drawings. Specific details are now referred to in particular to the drawings, and it is emphasized that the illustrated embodiments are exemplary and for the purpose of illustrative discussion of embodiments of this disclosure. In this regard, the description taken in conjunction with the drawings will make it apparent to those skilled in the art how embodiments of this disclosure can be practiced.

[0018] Figure 1 This illustrates the reaction mechanism of the synthetic polymer according to some embodiments.

[0019] Figure 2 The reaction scheme for synthesizing the polymer in Example 1 is shown.

[0020] Figure 3 Exemplary filters are shown according to some embodiments. Detailed Implementation

[0021] Other objects and advantages of this disclosure will become apparent from the following description taken in conjunction with the accompanying drawings, among the benefits and improvements already disclosed. Detailed embodiments of this disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely illustrative of the disclosure as it may be embodied in various forms. Furthermore, each example of the various embodiments of this disclosure is provided in an illustrative and non-limiting manner.

[0022] All prior patents and publications mentioned in this article are incorporated herein by reference in their entirety.

[0023] Throughout this specification and claims, unless the context clearly specifies otherwise, the following terms shall have the meanings explicitly associated herein. As used herein, the phrases “in one embodiment,” “in another embodiment,” and “in some embodiments” do not necessarily refer to the same embodiment, although they may refer to the same embodiment. Furthermore, as used herein, the phrases “in another embodiment” and “in some other embodiments” do not necessarily refer to different embodiments, although they may refer to different embodiments. All embodiments of this disclosure are intended to be combined without departing from the scope or spirit of this disclosure.

[0024] In this application, unless explicitly stated in the context or otherwise, (i) the term “a” is to be understood as “at least one”; (ii) the term “or” is to be understood as “and / or”; (iii) the terms “comprising” and “including” are to be understood as including the listed components or steps, whether or not they are presented by themselves or together with one or more other components or steps; (iv) the term “about / approximately” is to be understood as a permissible standard deviation, as understood by one of ordinary skill in the art; and (v) where a range is provided, endpoints are included. In some embodiments, unless otherwise specified or explicitly stated in the context, the term “about / approximately” means a range of values ​​falling within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% or less in any direction of the specified reference value (except where such a value would exceed 100% of the possible value). Furthermore, unless the context explicitly specifies otherwise, the term "based on" is non-exclusive and allows for reliance on other factors not described. The meaning of "in" includes both "within" and "on".

[0025] As used herein, the term "between" does not necessarily require direct proximity to other elements. Generally, this term refers to a configuration in which something is sandwiched between two or more other elements. At the same time, the term "between" can describe something directly adjacent to two opposing elements. Therefore, in any or more of the embodiments disclosed herein, a particular structural member arranged between two other structural elements can: be directly arranged between both other structural elements such that the particular structural member is in direct contact with both other structural elements; be directly adjacent to only one of the two other structural elements such that the particular structural member is in direct contact with only one of the two other structural elements; be directly adjacent to only one of the two other structural elements such that the particular structural member is not in direct contact with only one of the two other structural elements, and there is another element that juxtaposes the particular structural member and one of the two other structural elements; be indirectly arranged between two other structural elements such that the particular structural member is not in direct contact with both other structural elements, and other features can be arranged therebetween; or any combination thereof.

[0026] As used in this article, "embedded" means that the first material is distributed throughout the second material.

[0027] As used herein, the term "alkyl" refers to a hydrocarbon chain group having 1 to 30 carbon atoms. Alkyl groups can be linked by single bonds. Alkyl groups having n carbon atoms can be designated as "C". n Alkyl group. For example, "C3 alkyl" may include n-propyl and isopropyl. Alkyl groups having a series of carbon atoms, such as 1 to 30 carbon atoms, may be specified as C1-C6. 30 Alkyl group. In some embodiments, the alkyl group is saturated (e.g., single bond). In some embodiments, the alkyl group is unsaturated (e.g., double and / or triple bond). In some embodiments, the alkyl group is straight-chain. In some embodiments, the alkyl group is branched. In some embodiments, the alkyl group is substituted. In some embodiments, the alkyl group is unsubstituted. In some embodiments, the alkyl group may include C1-C1 bonds. 12 Alkyl, C1-C 11 Alkyl, C1-C 10The alkyl group comprises at least one of, or substantially comprises, or optionally comprises the group consisting of, at least one of, C1-C9 alkyl, C1-C8 alkyl, C1-C7 alkyl, C1-C6 alkyl, C1-C4 alkyl, and C1-C3 alkyl, or any combination thereof. In some embodiments, the alkyl group may comprise at least one of, or substantially comprises, or optionally comprises the group consisting of, at least one of, methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, isobutyl, sec-butyl, n-pentyl, 1,1-dimethylethyl (tert-butyl), n-pentyl, isopentyl, n-hexyl, isohexyl, 3-methylhexyl, 2-methylhexyl, octyl, decyl, dodecyl, octadecyl, or any combination thereof.

[0028] As used herein, the term "aryl" refers to a monocyclic or polycyclic aromatic hydrocarbon compound. The term "aryl" refers to an aromatic ring comprising carbon and hydrogen atoms. The number of carbon atoms in an aromatic hydrocarbon can range from 5 to 100 carbon atoms. In some embodiments, the aromatic hydrocarbon has 5 to 20 carbon atoms. For example, in some embodiments, the aromatic hydrocarbon has 6 to 8 carbon atoms, 6 to 10 carbon atoms, 6 to 12 carbon atoms, 6 to 15 carbon atoms, or 6 to 20 carbon atoms. When used as a modifier, the term "monocyclic" refers to an aromatic hydrocarbon having a single aromatic ring structure. When used as a modifier, the term "polycyclic" refers to an aromatic hydrocarbon having more than one aromatic ring structure, which may be a fused, bridged, helical, or otherwise bonded ring structure. The term "alkyl-substituted aromatic hydrocarbon" refers to an aromatic hydrocarbon containing one or more alkyl substituents. In some embodiments, the alkyl-substituted aromatic hydrocarbon may include at least one of monoalkylbenzenes, dialkylbenzenes, trialkylbenzenes, tetraalkylbenzenes, or any combination thereof. Aromatic hydrocarbons may be referred to as Ar in this document. Examples of aryl groups include (but are not limited to) phenyl, biphenyl, naphthyl, etc.

[0029] Synthetic aromatic fluorinated polymers

[0030] In some aspects, this disclosure relates to the synthesis of polymers comprising linear aromatic fluorinated polymers. The polymers can be synthesized in a single step via a metal-free superacid-catalyzed polyhydroxylation reaction of an active ketone (e.g., trifluoroacetone or hexafluoroacetone) with an unactivated polycyclic aromatic hydrocarbon (e.g., biphenyl). The polymerization can be carried out at room temperature in trifluorosulfonic acid (TFSA) or a mixture of TFSA and dichloromethane (DCM).

[0031] In some embodiments, preparing the disclosed polymer includes adding a first compound to a second compound. In some embodiments, the first compound may be an active ketone, including (but not limited to) trifluoroacetone or hexafluoroacetone. In some embodiments, the second compound may be a hydrocarbon, including (but not limited to) biphenyl.

[0032] In some embodiments, R is an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group.

[0033] In some embodiments, when R is a substituted alkyl group, the substituted alkyl group is a haloalkyl group, such as a fluoroalkyl group, a chloroalkyl group, an iodoalkyl group, or a bromoalkyl group. In some embodiments, when R is a substituted aryl group, the substituted aryl group is a haloaryl group, such as a fluoroaryl group, a chloroaryl group, an iodoaryl group, or a bromoaryl group. In some embodiments, when R' is a substituted aryl group, the substituted aryl group is a substituted biphenyl group, a substituted benzene group, a substituted p-triphenyl group, a substituted triphenyl group, or a substituted tetraphenyl group. In some embodiments, when R is a substituted alkyl group, the substituted alkyl group comprises at least two substituents. In some embodiments, when R is a substituted aryl group, the substituted aryl group comprises at least two substituents.

[0034] In some embodiments, R is methyl. In some embodiments, when R is a substituted alkyl group (such as a fluorinated methyl group), R is CH2F, CHF2, or CF3.

[0035] In some embodiments, when R is an aryl group, the aryl group includes a plurality of phenyl groups, such as biphenyl, p-triphenyl, triphenyl, or tetraphenyl. In some embodiments, at least one of the phenyl groups is substituted with at least one fluorine group.

[0036] In some embodiments, R' is an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. In some embodiments, when R' is a substituted alkyl group, the substituted alkyl group is a haloalkyl group, such as a fluoroalkyl group, a chloroalkyl group, an iodoalkyl group, or a bromoalkyl group. In some embodiments, when R' is a substituted aryl group, the substituted aryl group is a substituted biphenyl group, a substituted benzene group, a substituted p-triphenyl group, a substituted triphenyl group, or a substituted tetraphenyl group. In some embodiments, when R' is a substituted alkyl group or a substituted aryl group, the substituted alkyl group or the substituted aryl group comprises at least two substituents.

[0037] In some embodiments, when R' is an aryl group, the aryl group includes a plurality of phenyl groups, such as biphenyl, p-triphenyl, triphenyl, or tetraphenyl. In some embodiments, at least one of the phenyl groups is substituted with at least one fluorine group.

[0038] In some embodiments, the disclosed polymer comprises repeating units having the formula (II):

[0039]

[0040] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0041] In some embodiments, the disclosed polymer comprises repeating units having the formula (III):

[0042]

[0043] In some embodiments, the polymer comprises repeating units having the formula according to formula (IV):

[0044]

[0045] Porous polymer membrane

[0046] Porous polymer membranes can be used to remove contaminants from a variety of fluids. Factors for selecting a polymer for a membrane include (but are not limited to) the polymer’s cleanliness (e.g., having minimal oligomer shedding), its chemical compatibility with the specific fluid from which it removes contaminants, and its solubility in a solvent at room temperature, making it suitable for polymer phase separation membrane formation methods such as NIPS (non-solvent-induced phase separation) and VIP (vapor-induced phase separation).

[0047] Polymers currently used in porous polymer membranes (which can be used in polymer phase separation membrane formation methods) include, but are not limited to, polysulfone, polyethersulfone, polyarylsulfone, polyvinylidene fluoride, cellulose polymers, polyacrylonitrile, and nylon. However, polymer membranes derived from these polymers have several chemical compatibility limitations when used in acidic (low pH), alkaline (high pH), and oxidizing environments. When exposed to these environments or used for the removal of contaminants from acidic, alkaline, or oxidizing fluids, these membranes can dissolve, degrade, rupture, or the polymer chains can break down and shed oligomers, thereby introducing different contaminants into the fluid. This makes them unsuitable or has a limited lifespan. Therefore, there is a need for polymers that do not suffer from these limitations but are soluble in common solvents and can be processed into porous membranes using polymer phase separation methods such as NIPS and VIPS. The polymers disclosed herein, aromatic fluoropolymers, address this need.

[0048] The membranes disclosed herein are prepared from polymers containing aromatic fluoropolymers or polymers incorporating fluorine groups, which can increase the chemical resistance and thermal stability of the polymer and therefore the membrane. This combination of properties provides potential applications in membrane applications. For example, membranes utilizing the polymers of this disclosure can use solvents and have demonstrated desired chemical resistance in acids (such as concentrated sulfuric acid) and bases (such as sodium hydroxide). Furthermore, membranes utilizing the polymers of this disclosure can also possess desired chemical resistance in a variety of solutions used throughout semiconductor manufacturing processes, such as Standard Clean 1 (SC1) solution used in RCA cleaning.

[0049] In some embodiments, the disclosed polymer can be separated in methanol as a white fibrous material and can be used to cast flexible, transparent plastic films. The separated polymer can be used to form porous membranes, for example, using immersion casting techniques. The separated membranes can be porous and exhibit chemical inertness and thermal stability.

[0050] The membranes disclosed herein can be used, for example, to dilute wet etching and cleaning (WEC) chemistry. In contrast, existing membranes (e.g., membranes utilizing polysulfone) suffer from poor compatibility with organic and acidic chemicals and also exhibit poor oxidation resistance due to carbon-oxygen (CO) bonds, which are readily degraded. The synthetic polymers of this disclosure may contain carbon-carbon (CC) bonds, and various functionalities can be designed into the polymers to achieve desired membrane morphologies.

[0051] Figure 1 This illustrates the reaction mechanism of the synthetic polymer according to some embodiments.

[0052] Membrane morphology

[0053] Films derived from the polymers disclosed herein can be formed in many different structures or morphologies.

[0054] In some embodiments, the membrane may be formed with a symmetrical morphology, wherein the pore sizes throughout the cross-section or thickness are very close to being the same.

[0055] In some embodiments, the membrane may be formed with an asymmetric (anisotropic) morphology, wherein the pore size may vary across the membrane thickness.

[0056] In some embodiments of asymmetric membranes, the aperture on one facet and region of the membrane is larger than the aperture on the opposite facet and region, such that the aperture increases across the cross-section from one facet or region to the other.

[0057] In some embodiments of asymmetric membranes, an asymmetric structure may exist in which the pore size is larger on opposite faces (and regions) of the membrane, while the central region of the membrane has a smaller pore size than either of the faces (e.g., an hourglass pore size profile), as described, for example, in UK Publication No. GB ​​2199786 A.

[0058] In some embodiments, the membranes may be formed as composite membranes. In this case, these membranes are formed as thin layers over a pre-formed porous membrane, as described, for example, in EP Patent No. 0772489B1. In some embodiments, the membranes may also be co-cast or formed as multilayer membranes. In this case, different casting solutions are applied simultaneously or in an alternating manner to the formation process, resulting in an integrated membrane in which each layer has a different pore size or morphology, as described, for example, in U.S. Patent No. 10751669. The above variations can be achieved in membranes prepared in the form of flat sheets or hollow fibers as disclosed herein.

[0059] In some embodiments, the porous membrane may be formed as a flat sheet membrane or a hollow fiber membrane and may be packaged as a filter cartridge.

[0060] This disclosure includes porous membrane configurations that exhibit useful or advantageous filtration properties, including a combination of high flux and relatively high bubble point (small pore size) and good retention, as well as chemical stability in acids and alkalis. These properties are superior to or show substantial improvements over prior and currently commercially available membrane products.

[0061] film thickness

[0062] The disclosed membrane may have any thickness suitable for its intended application. For example, the disclosed membrane may have a thickness in the range of about 1 µm to about 1000 µm, about 1 µm to about 900 µm, about 1 µm to about 800 µm, about 1 µm to about 700 µm, about 1 µm to about 600 µm, about 1 µm to about 500 µm, about 1 µm to about 400 µm, about 1 µm to about 300 µm, about 1 µm to about 200 µm, about 1 µm to about 100 µm, or any range or subrange thereof. For example, in some embodiments, the disclosed membrane may have a thickness in the range of about 3 µm to about 200 µm. In some embodiments, the disclosed membrane may have a thickness in the range of about 5 µm to about 150 µm. In some embodiments, the disclosed membrane may have a thickness in the range of about 10 µm to about 100 µm. In some embodiments, the disclosed membrane may have a thickness in the range of about 15 µm to about 80 µm.

[0063] Any of the various characterization techniques known in this field can be used to measure film thickness, such as scanning electron microscopy (SEM), atomic force microscopy (AFM), etc.

[0064] Membrane characteristics

[0065] In some embodiments, membranes utilizing the polymers of this disclosure can be described by physical characteristics including pore size, bubble point, and porosity. Membranes used for filters can have any pore size that allows the membrane to function effectively as a filter (e.g., as described herein), including pores of a size considered to be that of a microporous filtration membrane or an ultrafiltration membrane (average pore size). Examples of usable porous membranes may have an average pore size ranging from about 0.001 µm to about 10 µm, wherein the pore size is selected based on one or more factors including: the particle size or type of impurities to be removed, pressure and pressure drop requirements, and the viscosity requirements of the liquid being processed through the membrane. Pore size is typically reported as the average pore size of porous materials, which can be measured using known techniques such as mercury porosimetry (MP), scanning electron microscopy (SEM), liquid displacement microscopy (LLDP), or atomic force microscopy (AFM).

[0066] Bubble point is also a known characteristic of porous membranes. The bubble point test method involves immersing a sample of the porous membrane in a liquid with a known surface tension and wetting it with the liquid, then applying gas pressure to one side of the sample. The gas pressure is gradually increased.

[0067] The minimum pressure at which gas flows through a sample is called the initial bubble point. The initial bubble point of the porous materials reported herein was determined as follows: a sample of the porous material was immersed in and wetted with ethoxy-nonafluorobutane HFE 7200 (purchased from 3M, St. Paul, MN) at a temperature of 20 to 25°C (e.g., 22°C). Gas pressure was applied to one side of the sample using compressed air and the gas pressure was gradually increased. All initial bubble point values ​​provided herein were measured using this procedure.

[0068] In some embodiments, the relationship between the bubble point and pore size is expressed by the Washburn equation or a modified version thereof (e.g., with pore size correction) to explain different pore geometries. In some embodiments, the bubble point pressure is related to the membrane's retention capacity. Further details regarding the bubble point are available, among others, in U.S. Patent No. 4,828,772, the entire contents of which are incorporated herein by reference.

[0069] Examples of available initial bubble point values ​​for porous membranes according to this disclosure, measured using the above-described procedure, may be in the range of about 1 to about 200 psi, about 1 to about 150 psi, about 1 to about 100 psi, about 10 to about 200 psi, about 10 to about 150 psi, about 10 to about 100 psi, about 10 to about 40 psi, about 20 to about 200 psi, about 20 to about 150 psi, about 20 to about 100 psi, about 40 to about 200 psi, about 40 to about 150 psi, about 40 to about 100 psi, about 60 to about 200 psi, about 60 to about 150 psi, about 60 to about 100 psi, about 80 to about 200 psi, about 80 to about 150 psi, about 100 to about 200 psi, about 100 to about 150 psi, about 150 to about 200 psi, or any and all of these ranges.

[0070] The porous membrane described herein may have any porosity that will allow the porous membrane to be effective as described herein. In some embodiments, the membrane may have a relatively high porosity, for example, at least 60%, 70%, or 80%. As used herein and in the field of porous bodies, the “porosity” (sometimes also referred to as void fraction) of a porous body is a measure of the percentage of void (i.e., “empty”) space in the body to the total volume of the body and is calculated as the fraction of the volume of voids in the body to the total volume of the body. A body with 0% porosity is entirely solid.

[0071] The membrane isopropanol (IPA) flow time, as reported herein, can be measured by passing 500 ml of isopropanol (IPA) fluid through a membrane with a diameter of 13.8 cm at 14.2 psi and 21 °C. 2The time taken to measure the effective surface area of ​​a membrane with a 47 mm membrane disk was determined. In some embodiments, the flow time is from about 10 seconds / 500 ml to about 19,000 seconds / 500 ml, from about 10 seconds / 500 ml to about 5,000 seconds / 500 ml, from about 10 seconds / 500 ml to about 1,000 seconds / 500 ml, from about 10 seconds / 500 ml to about 800 seconds / 500 ml, from about 10 seconds / 500 ml to about 500 seconds / 500 ml, from about 100 seconds / 500 ml to about 10,000 seconds / 500 ml, from about 100 seconds / 500 ml to about 5,000 seconds / 500 ml, from about 100 seconds / 500 ml to about 1,000 seconds / 500 ml, from about 100 seconds / 500 ml to about 800 seconds / 500 ml, from about 100 seconds / 500 ml to about 500 seconds / 500 ml, and from about 500 seconds / 500 ml to about 10,000 seconds / 500 ml. The range of approximately 500 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 1,000 seconds / 500 ml, approximately 500 seconds / 500 ml to approximately 800 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 10,000 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 1,665 seconds / 500 ml, approximately 845 seconds / 500 ml to approximately 1,000 seconds / 500 ml, approximately 1,000 seconds / 500 ml to approximately 10,000 seconds / 500 ml, approximately 1,000 seconds / 500 ml to approximately 5,000 seconds / 500 ml, approximately 20 seconds / 500 ml to approximately 2,500 seconds / 500 ml, or all ranges and subranges thereof.

[0072] In some embodiments, this disclosure includes a porous membrane having an aromatic fluoropolymer, wherein the membrane has an initial bubble point of 1 to 200 psi and an IPA flow time in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml. In some embodiments, the aromatic fluoropolymer comprises one or more monomer units having formula (I).

[0073]

[0074] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0075] In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial foaming point of 10 to 20 psi and an IPA flow time of 200 to 400 seconds / 500 ml. In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial foaming point of 20 to 40 psi and an IPA flow time of 400 to 1000 seconds / 500 ml. In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial foaming point of 40 to 60 psi and an IPA flow time of 1000 to 2000 seconds / 500 ml. In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial foaming point of 60 to 80 psi and an IPA flow time of 2000 to 3000 seconds / 500 ml. In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial foaming point of 80 to 100 psi and an IPA flow time of 3000 to 4000 seconds / 500 ml. In some embodiments, the porous membrane comprises an aromatic fluoropolymer having an initial bubble point of 100 to 120 psi and an IPA flow time of 4000 to 5000 seconds / 500 ml.

[0076] In some embodiments, the membranes disclosed herein exhibit chemical stability and chemical resistance to acids (such as concentrated sulfuric acid). In some embodiments, chemical stability in concentrated sulfuric acid can be demonstrated by measuring the initial bubble point of the membrane before immersion in 96% sulfuric acid and after 3 days, wherein the change in the initial bubble point of the membrane is less than 20%, less than 15%, or less than 10%, wherein the initial bubble point of the membrane is measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of approximately 22°C. In some embodiments, chemical stability in concentrated sulfuric acid can be further demonstrated by visual inspection, either by the membrane not changing color and / or dissolving during visual inspection after immersion in 96% sulfuric acid for 3 days.

[0077] In some embodiments, the membranes disclosed herein exhibit chemical stability and chemical resistance to alkalis (such as sodium hydroxide). In some embodiments, chemical stability in sodium hydroxide can be demonstrated by the membrane not changing color and / or dissolving upon visual inspection when immersed in 0.04% by weight sodium hydroxide for 1 day.

[0078] In some embodiments, the polymers disclosed herein do not include polyarylethers, polysulfones, or polytetrafluoroethylene. In some embodiments, the polymers disclosed herein do not include ether bonding.

[0079] In some embodiments, the polymer comprises only carbon-carbon bonds in the main chain of the polymer disclosed herein.

[0080] In some embodiments, the polymers disclosed herein comprise aromatic fluoropolymers. In some embodiments, the polymers disclosed herein are linear. In some embodiments, the polymers disclosed herein are linear aromatic fluoropolymers.

[0081] Functionalized porous polymer membranes

[0082] Membranes derived from the polymers disclosed herein can be functionalized using a number of different techniques.

[0083] For example, in some embodiments, the porous membrane may be a coated porous membrane, wherein the porous membrane (e.g., a porous polymer filter layer) has a polymer membrane coating on one or more surfaces of the porous membrane, as described, for example, in U.S. Patent No. 11,413,586. In some embodiments, the polymer membrane coating is a membrane coating comprising a crosslinked polymer. In some embodiments, the polymer membrane coating may be porous or non-porous.

[0084] The membrane may be continuous or semi-continuous over a portion of one or more surfaces of a porous membrane (e.g., a porous polymer membrane layer), meaning that the membrane may be interspersed but may cover the substantial portion of the porous membrane.

[0085] In some embodiments, the porous membrane may have a coating of one or more polymeric monomers and combinations thereof having a positive, negative, or neutral charge in an organic liquid, as described, for example, in U.S. Publication No. 2022 / 0134287. The coating may comprise an organic backbone formed from the polymeric monomers. The coating may comprise a crosslinking agent and monomers or copolymers. In some embodiments, the various polymeric monomers involve various characteristics that may differ from or be identical to each other. Polymerization and crosslinking of the polymerizable monomers on the porous membrane substrate results in at least a portion and up to the entire surface of the porous membrane (including the inner pore surfaces of the porous membrane) being modified by the crosslinked polymer. In some embodiments, the coating may, as needed, cover a large portion of the porous membrane surface with a crosslinked polymer composition, from greater than 0% to 100%.

[0086] In some embodiments, the porous membrane may be grafted to modify the porous membrane and to directly bond polymeric monomers, copolymers, crosslinking agents, or combinations thereof to the porous membrane material, as described, for example, in U.S. Publication No. 2022 / 0032282. In some embodiments, a combination of techniques may be used on the porous membrane, such as a membrane having a crosslinked portion and a grafted portion. Examples also include crosslinked grafted portions. Crosslinking and grafting techniques include a variety of coatings, from greater than 0% to 100%, onto the surface of the porous membrane as needed.

[0087] In some embodiments, this disclosure relates to porous membranes comprising blends of polymers having formula (IV) and other polymers or copolymers, as described, for example, in EP 1149625 B1. In some embodiments, this disclosure relates to membranes wherein other polymers or copolymers may have fluorinated or nonfluorinated organic backbones and combinations thereof having positive, negative, or positive charges.

[0088] In some embodiments, the functionalized membranes disclosed herein can be used to remove ions, organic matter, and metallic contaminants from organic and aqueous liquids.

[0089] Filters and Filter Devices

[0090] In some embodiments, the filter comprises the membrane of this disclosure. For filtration purposes, the filter may comprise a filter membrane responsible for removing unwanted substances from fluid passing through the filter membrane. The filter membrane may be in the form of a flat sheet, which may be wound (e.g., spiral), flattened, pleated, or disc-shaped. The filter membrane may also be in the form of hollow fibers. The filter membrane may be housed within a housing or otherwise supported such that the fluid being filtered enters the filter inlet and needs to pass through the filter membrane before passing through the filter outlet. Figure 3 An exemplary filter 100 is shown, having a filter cartridge 110 disposed within a housing 120. A membrane 130 is disposed within the filter cartridge and arranged around a core 140, which provides support for the membrane 130. End caps 150 and 160 are attachable to opposite ends of the housing 120 and provide openings for fluids to be filtered and / or purified to enter and exit the filter 100.

[0091] Filter membranes can be configured with a porous structure having an average pore size selectable based on the intended use of the filter, i.e., the type of filtration performed by the filter. Typical pore sizes are in the micrometer or submicrometer range, such as from about 0.001 µm to about 10 µm. Membranes with an average pore size of about 0.001 to about 0.1 µm are sometimes classified as ultrafiltration membranes. Membranes with pore sizes between about 0.1 and 10 µm are sometimes called microporous membranes.

[0092] Membranes with pore sizes in the micrometer or submicrometer range can effectively remove unwanted substances (i.e., impurities) through sieving mechanisms, non-sieving mechanisms, or both via free-flowing flow. A sieving mechanism is a filtration mode in which particles are removed by free-flowing flow due to mechanical retention on the membrane surface. The membrane mechanically intervenes in particle movement and retains particles within the filter, mechanically preventing particle flow through the filter. Sometimes, the particles can be larger than the filter pores. A non-sieving filtration mechanism is a filtration mode in which suspended particles or dissolved material contained in the fluid flow passing through the membrane are retained by the membrane in a manner not merely mechanical (e.g., it includes an electrostatic mechanism). Through the electrostatic mechanism, particles or dissolved impurities are electrostatically attracted and retained on the filter surface and removed by free-flowing flow; the particles may be dissolved or may be solids with a particle size smaller than the pore size of the filter medium.

[0093] The filter comprising the membrane can take any desired form suitable for the filtration application. The material forming the filter can be a structural component of the filter itself and provide the desired architecture for the filter. The membrane can be any desired shape or configuration.

[0094] The porous membranes disclosed herein can be used in a variety of applications or uses. In some embodiments, the porous membranes can be used with any type of industrial or life science application that requires high-purity liquid materials as input. In many life science applications, porous membranes are used to remove biological contaminants such as bacteria, viruses, endotoxins, etc. In many industrial applications, porous membranes are used to remove particulate matter. Semiconductor processing requires ultra-clean fluids to prevent defects. The membranes disclosed herein can be used to remove trace contaminants such as particles, metal ions, aggregates, etc. The uses of the membranes disclosed herein are not limited to the applications mentioned above. Any filtration or purification application requiring cleanliness, inertness, stability, and high filtration efficiency can benefit from using the membranes disclosed herein. Further non-limiting examples of these applications include methods for preparing microelectronic or semiconductor devices, such as in the filtration or purification of liquid processing materials used in wet etching and cleaning or photolithography; diagnostic applications; inkjet applications; filtration of fluids for the pharmaceutical industry; metal removal; ultrapure water production; industrial and surface water treatment; filtration of fluids for medical applications (e.g., intravenous applications); filtration of biological fluids, such as blood (e.g., for virus removal); filtration of fluids for the food and beverage industry; beer filtration; clarification; filtration of fluids containing antibodies and / or proteins; filtration of fluids containing nucleic acids; cell harvesting; filtration of cell culture media; and / or ventilation applications.

[0095] Examples of contaminants present in processing liquids or solvents used to prepare microelectronic or semiconductor devices may include metal ions dissolved in the liquid, solid particles suspended in the liquid, and gelling or coagulating materials present in the liquid.

[0096] As discussed herein, the porous membrane may be a single layer or multiple layers, for example, combined with another filter material to form a composite filter membrane. In either case, the membrane can be used to remove dissolved or suspended contaminants or impurities from liquid flowing through the membrane via a sieving mechanism or a non-sieving mechanism, or via a combination of both sieving and non-sieving mechanisms.

[0097] Membrane preparation

[0098] In some embodiments, this disclosure relates to methods for preparing porous membranes using the polymers of this disclosure. For example, in some embodiments, this disclosure relates to methods for preparing porous membranes using the polymers of this disclosure, such as polymers comprising one or more monomer units having the following formula:

[0099] .

[0100] In some embodiments, the method for preparing the disclosed porous membrane includes the following steps: preparing a solution of the disclosed aromatic fluoropolymer and a suitable solvent; casting the prepared solution onto a substrate (e.g., a glass substrate); and immersing the casting solution to form a porous membrane.

[0101] Any of a variety of solvents that can be used to prepare solutions of the disclosed polymer can be used. For example, in some embodiments, suitable solvents include N-methyl-2-pyrrolidone (NMP), isopropanol (IPA), or a combination of both.

[0102] Any of various casting methods can be used to cast a solution of the disclosed polymer onto a substrate to prepare the membrane of this disclosure. For example, in some embodiments, casting can be performed using a membrane applicator, such as a TQC automated membrane applicator. In some embodiments, the porous membrane thickness can be controlled by varying the dimensions of membrane applicator components (e.g., blades or cutters on the membrane applicator).

[0103] For the purpose of casting a solution of the disclosed polymer during the preparation of the disclosed porous membrane, any of a variety of substrates can be used. For example, in some embodiments, the substrate may be a glass substrate. Alternatively, the substrate may be a porous polymer substrate. By casting onto the porous polymer substrate, a composite membrane having a first layer of the disclosed polymer and a second layer comprising the porous polymer substrate can be formed. Any of a variety of porous polymer substrates can be used. For example, in some embodiments, the porous polymer substrate may comprise a fluorinated polymer, such as polytetrafluoroethylene (PTFE).

[0104] In some embodiments, immersion includes immersing a casting solution of the disclosed polymer in a liquid. In some embodiments, the liquid may be any of a variety of liquids suitable for providing porous membranes. For example, a casting solution of the disclosed polymer may be immersed in a water bath (e.g., maintained at room temperature) to form a porous membrane sheet (e.g., a membrane).

[0105] Example

[0106] Example 1: Synthesis of an exemplary polymer A

[0107] This example demonstrates the synthesis of an exemplary polymer (“Polymer A”).

[0108] A solution of biphenyl (25.0 g, 162 mmol) in 60 mL of dichloromethane was added via an addition funnel to a reactor (2 L) equipped with a head-mounted mechanical stirrer. The solution was stirred at 400 rpm. Then, trifluoromethanesulfonic acid (TFSA) (48.6 g, 324 mmol) in 60 mL of dichloromethane was added via a metering pump over 20 minutes. The solution was then cooled to -20°C. Subsequently, trifluoroacetone (25.1 g, 224 mmol) was added in a single injection using a syringe. The reaction mixture was gradually heated to 30°C over 1 hour. The reaction mixture was stirred at 30°C for 8 hours. The reaction mixture was then cooled to 2°C, and a solution of potassium carbonate (26.9 g, 194.5 mmol) in 27 mL of deionized water was added dropwise to the reaction mixture over approximately 10 minutes using a syringe pump. The resulting dark brown suspension was slowly poured into 600 mL of methanol to separate the exemplary polymer. The white precipitate was filtered, washed with 50 mL of methanol, and dried overnight in a convection oven at 80 °C. A white fibrous polymer was obtained (38.5 g, 95.6% yield, Mw = 55 kDa, PDI = 2.01). 1 H and 19 The polymer was characterized by F-NMR.

[0109] Example 2: Preparation of membranes using polymer A

[0110] This example demonstrates the preparation of an exemplary porous membrane comprising an exemplary polymer synthesized as demonstrated in Example 1.

[0111] Prior to membrane preparation, polymer A from Example 1 was dried overnight at 60°C to remove any residual solvent and water. A membrane casting formulation was prepared according to the exemplary formulation described in Table 1. The exemplary formulation contained polymer A as demonstrated in Example 1, N-methyl-2-pyrrolidone (NMP), and isopropanol (IPA). The membrane casting formulation was metered and cast at a rate of 1 inch / second through a control slot between casting blades on a glass plate of a TQC automated membrane applicator (purchased from TQC Sheen BV, Nieuwerkerk aan den Ijssel, Netherlands). The cast membrane was then immersed in a water bath maintained at room temperature. The membrane thickness was controlled by using blades of different sizes. In this example, the membrane had a thickness of 75 µm. The porous membrane was washed in water for several hours. The IPA flow time and initial bubble point were tested using the method described above. The results are shown in Table 1 below. As can be seen, increasing the polymer weight percentage increases the initial bubble point and IPA flow time.

[0112] Table 1: Membrane casting formulations and membrane properties in Example 2

[0113]

[0114] Example 3: Synthesis of an exemplary polymer B

[0115] This example demonstrates the synthesis of an exemplary polymer (“Polymer B”).

[0116] Polymer B was synthesized according to the following procedure. Trifluoroacetone (6.5 ml, 72.8 mmol), biphenyl (9.2 g, 59.54 mmol), and 60 ml of dichloromethane were placed in a three-necked round-bottom flask equipped with a mechanical stirrer and a top condenser. The solution was cooled to 0°C using ice. Trifluoromethanesulfonic acid (TFSA) (25 mL, 291 mmolole) was added in portions using a dropping funnel, and the reaction mixture was stirred at this temperature for 1 hour. The temperature was then gradually increased to room temperature, and the reaction mixture was stirred at this temperature for 3 hours. After the reaction was complete, it was cooled to 2°C and neutralized with a saturated potassium carbonate solution. The resulting dark brown solution was then slowly poured into methanol to separate the polymer. The precipitated white solid was filtered, washed with methanol (300 mL), and dried overnight in an oven at 80°C to give 14.12 g of white fibrous polymer in 95.5% yield. 1 The molecular weight of the polymer was characterized by 1H-NMR and gel permeation chromatography (GPC). A white fibrous polymer (Mw = 154 kDa, PDI = 2.72) was obtained. 1 H and 19 F-NMR characterizes the polymer.

[0117] Example 4: Preparation of a membrane using polymer B prepared according to Example 3

[0118] A membrane casting formulation was prepared according to the exemplary formulations described in Table 2. The formulation contained polymer B, NMP, and IPA as demonstrated in Example 3. The membrane casting formulation was poured onto the glass surface of a TQC automated membrane applicator (purchased from TQC Sinen, Völkell-sur-Isel, Netherlands) and the membrane was cast at a rate of 1 inch / second. The cast membrane was then immersed in a water bath maintained at room temperature. In this example, the membrane had a thickness of 75 µm. The porous membrane was washed in water for several hours. Membrane performance (including IPA flow time and initial bubble point) was tested, and the results are shown in Table 2 below.

[0119] Table 2. Example 3: Membrane casting formulations and membrane properties

[0120]

[0121] Example 5: Synthesis of an exemplary polymer C

[0122] This example demonstrates the synthesis of an exemplary polymer (“Polymer C”) according to this disclosure.

[0123] A solution of biphenyl (18.4 g, 119 mmol) in 60 mL of dichloromethane was added via a funnel to a reactor (2 L) equipped with an overhead mechanical stirrer. The solution was stirred at 400 rpm. Then, trifluoromethanesulfonic acid (TFSA) (87.3 g, 582 mmol) was added via a metering pump to 60 mL of dichloromethane over 20 minutes. The solution was then cooled to -20°C. Subsequently, trifluoroacetone (18.4 g, 164 mmol) was added in a single injection using a syringe. The reaction mixture was then gradually heated to 30°C over 1 hour. The reaction mixture was then stirred at 30°C for 4 hours. The reaction mixture was cooled to 2°C, and a solution of potassium carbonate (48.3 g, 349 mmol) in 50 mL of deionized water was added dropwise to the reaction mixture using a syringe pump over approximately 10 minutes. The resulting dark brown suspension was slowly poured into 600 mL of methanol to separate the polymer. The white precipitate was filtered, washed with 50 mL of methanol, and dried overnight in a convection oven at 80 °C. A white fibrous polymer was obtained (27.0 g, 91.52% yield, Mw = 992.7 kDa, PDI = 3.92).

[0124] Example 6: Membrane preparation using polymer C

[0125] This example demonstrates the preparation of an exemplary porous membrane comprising an exemplary polymer synthesized as demonstrated in Example 5.

[0126] Prior to membrane preparation, the exemplary polymer C was dried overnight at 60°C to remove any residual solvent and water. A membrane casting formulation was prepared according to the exemplary formulation described in Table 3. The exemplary formulation contained polymer C, NMP, and IPA as demonstrated in Example 5. The membrane casting formulation was poured onto the glass surface of a TQC automated membrane applicator, and the membrane was cast at a rate of 1 inch / second. The cast membrane was immersed in a water bath maintained at room temperature. In this example, the membrane had a thickness of 75 µm. The membrane was washed in water for several hours and its properties, including IPA flow time and initial bubble point, were tested according to the methods described herein, and the results are shown in Table 3 below.

[0127] Table 3. Example 6: Membrane casting formulations and membrane properties

[0128]

[0129] Example 7: Chemical resistance of a membrane containing an exemplary polymer in 96% sulfuric acid.

[0130] The chemical stability of a 47 mm membrane disc prepared according to Example 4 was tested in concentrated sulfuric acid. The membrane was first pre-wetted with HFE-7200 solvent, and then the initial bubble point (BP) in HFE-7200 solvent was measured using the method described above. The same membrane disc was exchanged in a DIW and immersed in 96 wt% sulfuric acid at room temperature under static conditions. After immersion, the membrane disc was removed and thoroughly washed in a DIW to remove any trace acid, pre-wetted in IPA to remove any residual water, and exchanged in HFE-7200 solvent for approximately 15 minutes using a shaker. The initial bubble point of the membrane was measured before and after immersion using the method described above, and the results are reported in the table below. The initial bubble point increased by only about 10.6% after three days of immersion compared to before immersion. The membrane is resistant and stable in sulfuric acid, as evidenced by the fact that the change in initial bubble point after immersion was less than 20% compared to the bubble point before immersion. During visual inspection after immersion, the film did not change color or dissolve, which is another indicator of its chemical stability in sulfuric acid.

[0131] Table 4. Initial foaming points before and after immersion in 96% sulfuric acid.

[0132]

[0133] Example 8: Chemical resistance of films containing exemplary polymers in sodium hydroxide

[0134] The chemical stability of the 47 mm membrane disc prepared according to Example 2 was tested in sodium hydroxide and compared with that of a polyvinylidene fluoride (PVDF) membrane. The membrane was immersed in sodium hydroxide for 24 hours at room temperature. The PVDF membrane immediately turned black, indicating its chemical instability in sodium hydroxide. The membrane prepared according to Example 2 did not change color or dissolve upon visual inspection, indicating that the membrane prepared according to Example 2 is chemically stable in sodium hydroxide.

[0135] Example 9: Chemical resistance in SC1

[0136] The chemical resistance of the membrane was tested in SC1 chemicals according to the following procedure. First, a membrane containing the disclosed polymer was pre-wetted with IPA and then exchanged with DIW. It was then immersed in SC1 chemicals for 7 days, which were freshly prepared by mixing 5 volumes of DIW with 1 volume of ammonium hydroxide and 1 volume of 30% H2O2. After immersion, the membrane was removed and thoroughly washed in DIW to remove any trace acid. The flow time of the membrane was then tested and compared with the flow time before immersion in SC1. The brittleness of the membrane immersed in peroxide was also tested, as measured by Instron, and the data are reported as elongation at break (%) in Table 1 below. No significant change in fracture strain was observed on the membrane immersed in peroxide.

[0137] Table 5. Composition of SC1 solution

[0138]

[0139] Table 6. DIW flow time of exemplary membranes after immersion in SC1

[0140]

[0141] Table 7. Fracture strain of exemplary membranes after immersion in H2O2

[0142]

[0143] Example 10: Chemical resistance of composite membranes

[0144] This example demonstrates the chemical resistance of an exemplary composite membrane in standard clean solutions of 1, 96 wt% sulfuric acid or hot sulfuric acid. The chemical resistance of the composite membrane is evaluated by measuring the stability of certain membrane properties, such as DIW flow time and bubble point as measured by HFE, as disclosed herein.

[0145] As disclosed herein, exemplary composite membranes were prepared by coating the disclosed polymer onto PTFE membrane sheets. The composite membrane sheets were then immersed in a standard Clean 1 (“SC1”) solution, a 96% by weight sulfuric acid solution, or a hot sulfuric acid solution for up to four weeks. The chemical resistance of the composite membranes was evaluated by quantifying the change in flow time and bubble point (%) compared to a control membrane not exposed to any of the solutions described in this example. The results are presented in Tables 8 through 10. The change in % for each of the DIW flow time and HFE-BP was calculated as the absolute difference between the immersed membrane and the control value divided by the control value.

[0146] Table 8. Stability of the composite membrane in SC1

[0147]

[0148] Table 9: Stability of the composite membrane in 96% sulfuric acid

[0149]

[0150] Table 10: Stability of the composite membrane in hot sulfuric acid at 70°C

[0151]

[0152] aspect

[0153] The following describes various aspects. It should be understood that any one or more of the features detailed in the following aspects may be combined with any one or more other aspects.

[0154] Aspect 1. A porous membrane comprising: a polymer having the following formula:

[0155] ,

[0156] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0157] Aspect 2. The porous membrane according to aspect 1, wherein when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C, the initial bubble point of the porous membrane ranges from 1 psi to 200 psi; and when measured at 14.2 psi, the isopropanol (IPA) flow time of the porous membrane ranges from 10 seconds / 500 ml to 19,000 seconds / 500 ml.

[0158] Aspect 3. The porous membrane according to aspect 1 or 2, wherein when the initial bubble point of the membrane is measured before and three days after immersion in 96% sulfuric acid, the change in the initial bubble point of the membrane does not exceed 20%, wherein the initial bubble point of the membrane is measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0159] Aspect 4. A porous membrane comprising: an aromatic fluoropolymer, wherein, when measured at a temperature of about 22°C using ethoxy-nonafluorobutane HFE 7200, the membrane has an initial bubble point in the range of 1 psi to 200 psi and an IPA flow time in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml when measured at 14.2 psi.

[0160] Aspect 5. The porous membrane according to aspect 4, wherein when the initial bubble point of the membrane is measured before immersing the membrane in 96% sulfuric acid and three days later, the change in the initial bubble point of the membrane does not exceed 20%, wherein the initial bubble point of the membrane is measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0161] Aspect 6. A porous membrane comprising: an aromatic fluoropolymer, wherein when the initial bubble point of the membrane is measured before and three days after immersion in 96% sulfuric acid, the change in the initial bubble point of the membrane does not exceed 20%, wherein the initial bubble point of the membrane is measured using ethoxy-nonafluorobutane HFE7200 at a temperature of about 22°C.

[0162] Aspect 7. The porous membrane according to any one of Aspects 4 to 6, wherein the aromatic fluoropolymer has the following formula:

[0163] ,

[0164] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0165] Aspect 8. The porous membrane according to any one of Aspects 1 to 7, wherein when R is a substituted alkyl group, the substituted alkyl group is a haloalkyl group.

[0166] Aspect 9. The porous membrane according to any one of Aspects 1 to 7, wherein when R' is a substituted alkyl group, the substituted alkyl group is a haloalkyl group.

[0167] Aspect 10. The porous membrane according to any one of Aspects 1 to 7, wherein when R' is a substituted aryl group, the substituted aryl group is a haloaryl group.

[0168] Aspect 11. The porous membrane according to any one of Aspects 1 to 7, wherein R' is biphenyl.

[0169] Aspect 12. The porous membrane according to any one of Aspects 1 to 7 or 11, wherein the polymer has the following formula:

[0170] .

[0171] Aspect 13. The porous membrane according to any one of Aspects 1 to 7 or 11, wherein R is CF3.

[0172] Aspect 14. The porous membrane according to aspect 11, wherein the biphenyl group is substituted with at least one fluorine group.

[0173] Aspect 15. The porous membrane according to any one of aspects 1 to 7, wherein R is methyl.

[0174] Aspect 16. The porous membrane according to any one of Aspects 1 to 7, wherein when R is a substituted alkyl or a substituted aryl, the substituted alkyl or the substituted aryl comprises at least two substituents.

[0175] Aspect 17. The porous membrane according to any one of Aspects 1 to 7, wherein when R' is a substituted alkyl or a substituted aryl, the substituted alkyl or the substituted aryl comprises at least two substituents.

[0176] Aspect 18. The porous membrane according to any one of Aspects 1 to 17, wherein the porous membrane comprises a symmetrical porous membrane or an asymmetrical porous membrane.

[0177] Aspect 19. The porous membrane according to any one of Aspects 1 to 18, wherein the polymer does not include polyarylether, polysulfone or polytetrafluoroethylene.

[0178] Aspect 20. The porous membrane according to any one of Aspects 1 to 19, wherein the polymer comprises only carbon-carbon bonds in the main chain of the polymer.

[0179] Aspect 21. The porous membrane according to any one of Aspects 1 to 20, wherein the polymer is an aromatic fluoropolymer.

[0180] Aspect 22. The porous membrane according to any one of Aspects 1 to 21, wherein the polymer is a linear aromatic fluoropolymer.

[0181] Aspect 23. The porous membrane according to any one of aspects 1 to 22, wherein the polymer is linear.

[0182] Aspect 24. A method comprising: preparing a porous membrane using a polymer of the following formula:

[0183] ,

[0184] Wherein R is an alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is an alkyl, substituted alkyl, aryl or substituted aryl.

[0185] Aspect 25. The method according to aspect 24, wherein preparing the polymer comprises adding a first compound to a second compound.

[0186] Aspect 26. The method according to aspect 25, wherein the first compound is an active ketone.

[0187] Aspect 27. The method according to aspect 26, wherein the active ketone comprises trifluoroacetone or hexafluoroacetone.

[0188] Aspect 28. The method according to aspect 25, wherein the second compound is a hydrocarbon.

[0189] Aspect 29. The method according to aspect 28, wherein the hydrocarbon comprises biphenyl.

[0190] Aspect 30. The method according to aspect 24, wherein when R is a substituted alkyl group, the substituted alkyl group is a haloalkyl group.

[0191] Aspect 31. The method according to aspect 24, wherein when R' is a substituted alkyl group, the substituted alkyl group is a haloalkyl group.

[0192] Aspect 32. The method according to aspect 24, wherein when R' is a substituted aryl group, the substituted aryl group is a haloaryl group.

[0193] Aspect 33. The method according to aspect 24, wherein R' is biphenyl.

[0194] Aspect 34. The method according to aspect 33, wherein the polymer has the following formula:

[0195] .

[0196] Aspect 35. The method according to aspect 34, wherein R is CF3.

[0197] Aspect 36. The method according to aspect 34, wherein the biphenyl group is substituted with at least one fluorine group.

[0198] Aspect 37. The method according to aspect 24, wherein the alkyl group is methyl.

[0199] Aspect 38. The method according to aspect 24, wherein when R is a substituted alkyl or a substituted aryl, the substituted alkyl or the substituted aryl comprises at least two substituents.

[0200] Aspect 39. The method according to aspect 24, wherein when R' is a substituted alkyl or a substituted aryl, the substituted alkyl or the substituted aryl comprises at least two substituents.

[0201] Aspect 40. The method according to aspect 24, wherein R' is biphenyl.

[0202] Aspect 41. The method according to aspect 24, wherein the porous membrane comprises a symmetrical porous membrane or an asymmetrical porous membrane.

[0203] Aspect 42. The method according to aspect 24, wherein the polymer does not include polyarylethers, polysulfones, or polytetrafluoroethylene.

[0204] Aspect 43. The method according to aspect 24, wherein the polymer comprises only carbon-carbon bonds in the main chain of the polymer.

[0205] Aspect 44. The method according to aspect 24, wherein the polymer is an aromatic fluoropolymer.

[0206] Aspect 45. The method according to aspect 24, wherein the polymer is a linear aromatic fluoropolymer.

[0207] Aspect 46. The method according to aspect 24, wherein the polymer is linear.

[0208] Aspect 47. A filter comprising a porous membrane according to any one of aspects 1 to 23.

[0209] Aspect 48. A porous membrane comprising: a polymer comprising one or more monomer units having the following formula:

[0210] ,

[0211] Wherein R is methyl, alkyl, substituted alkyl, aryl or substituted aryl, and wherein R' is alkyl, substituted alkyl, aryl or substituted aryl.

[0212] Aspect 49. The porous membrane according to aspect 48, wherein R is an alkyl group substituted with a halogen.

[0213] Aspect 50. The porous membrane according to aspect 49, wherein the halogen-substituted alkyl group is a fluorine-substituted alkyl group.

[0214] Aspect 51. The porous membrane according to any one of Aspects 48 to 50, wherein R' is an aryl group substituted with a halogen.

[0215] Aspect 52. The porous membrane according to aspect 51, wherein the halogen-substituted aryl group is a fluorine-substituted aryl group.

[0216] Aspect 53. The porous membrane according to any one of Aspects 48 to 52, wherein R' is biphenyl.

[0217] Aspect 54. The porous membrane according to aspect 53, wherein the biphenyl is substituted with at least one fluorine substituent.

[0218] Aspect 55. The porous membrane according to aspect 53, wherein the polymer comprises repeating units having the following formula:

[0219] .

[0220] Aspect 56. The porous membrane according to aspect 48, wherein the polymer comprises repeating units having the following formula:

[0221] .

[0222] Aspect 57. The porous membrane according to any one of Aspects 48 to 56, wherein the polymer of the porous membrane does not include polyarylether, polysulfone, or polytetrafluoroethylene.

[0223] Aspect 58. The porous membrane according to any one of Aspects 48 to 57, having: an initial bubble point of the porous membrane in the range of 1 psi to 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C; and an isopropanol (IPA) flow time of the porous membrane in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml when measured at 14.2 psi.

[0224] Aspect 59. The porous membrane according to any one of Aspects 48 to 58, characterized in that it has an absolute difference of not more than about 20% between (i) the initial bubble point of the porous membrane measured not less than about 3 days before immersion in the solution, and (ii) the initial bubble point of the porous membrane measured not less than about 3 days after immersion in the solution; wherein the solution is (1) a 96% by weight sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and the initial bubble point of (i) and (ii) is measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0225] Aspect 60. A porous membrane comprising an aromatic fluoropolymer, said porous membrane having: an initial bubble point in the range of 1 psi to 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C; and an IPA flow time in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml when measured at 14.2 psi.

[0226] Aspect 61. The porous membrane according to aspect 60, characterized in that it has an absolute difference of no more than about 20% between (i) the initial bubble point of the porous membrane measured about 3 days before immersion in the solution and (ii) the initial bubble point of the porous membrane measured after immersion in the solution; wherein the solution is (1) a 96 wt% sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and the initial bubble points of (i) and (ii) are measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0227] Aspect 62. A porous membrane comprising an aromatic fluoropolymer, the porous membrane being characterized by having an absolute difference of no more than about 20% between: (i) the initial bubble point of the porous membrane measured not less than about 3 days before immersion in a solution, and (ii) the initial bubble point of the porous membrane measured not less than about 3 days after immersion in a solution; wherein the solution is (1) a 96 wt% sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and the initial bubble points of (i) and (ii) are measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of about 22°C.

[0228] Aspect 63. The porous membrane according to any one of aspects 48 to 62, wherein the porous membrane has a thickness of about 30 µm to about 200 µm.

[0229] Aspect 64. The porous membrane according to aspect 63, wherein the porous membrane has a thickness of about 50 µm to about 100 µm.

[0230] Aspect 65. The porous membrane according to aspect 64, wherein the porous membrane has a thickness of about 75 µm.

[0231] Aspect 66. A composite membrane comprising a porous membrane according to any one of aspects 48 to 66 and a porous polymer substrate support.

[0232] Aspect 67. The composite membrane according to aspect 66, wherein the second

[0233] It should be understood that changes may be made in details, particularly in the shape, size, and arrangement of the construction materials and parts, without departing from the scope of this disclosure. This specification and the described embodiments are exemplary, and the true scope and spirit of this disclosure are defined by the following claims.

Claims

1. A porous membrane comprising: Polymer, the polymer comprising one or more monomer units having the following formula: ， Wherein R is methyl, alkyl, substituted alkyl, aryl, or substituted aryl, and Wherein R' is an alkyl, a substituted alkyl, an aryl, or a substituted aryl.

2. The porous membrane according to claim 1, wherein R is an alkyl group substituted with a halogen.

3. The porous membrane according to claim 2, wherein the halogen-substituted alkyl group is a fluorine-substituted alkyl group.

4. The porous membrane according to claim 1, wherein R' is an aryl group substituted with halogen.

5. The porous membrane according to claim 4, wherein the halogen-substituted aryl group is a fluorine-substituted aryl group.

6. The porous membrane according to claim 1, wherein R' is biphenyl.

7. The porous membrane according to claim 6, wherein the biphenyl group is substituted with at least one fluorine substituent.

8. The porous membrane of claim 6, wherein the polymer comprises repeating units having the following formula: 。 9. The porous membrane of claim 1, wherein the polymer comprises repeating units having the following formula: 。 10. The porous membrane of claim 1, wherein the polymer of the porous membrane does not include polyarylether, polysulfone, or polytetrafluoroethylene.

11. The porous membrane according to claim 1, comprising: The initial bubbling point of the porous membrane in the range of 1 psi to 200 psi, measured using an ethoxy-nonafluorobutane HFE 7200 at a temperature of approximately 22°C; and Isopropanol (IPA) flow time of the porous membrane, ranging from 10 seconds / 500 ml to 19,000 seconds / 500 ml, when measured at 14.2 psi.

12. The porous membrane according to claim 1, characterized in that it has an absolute difference of no more than about 20% between the following: (i) The initial bubble point of the porous membrane, measured not less than about 3 days before being placed in the solution, and (ii) The initial bubbling point of the porous membrane after being placed in the solution for no less than about 3 days; The solution is (1) a 96% by weight sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and The initial bubble points mentioned in (i) and (ii) were measured at a temperature of about 22°C using ethoxy-nonafluorobutane HFE 7200.

13. A porous membrane comprising an aromatic fluoropolymer, said porous membrane having: The initial bubbling point in the range of 1 psi to 200 psi when measured using ethoxy-nonafluorobutane HFE 7200 at a temperature of approximately 22°C; and IPA flow time, measured at 14.2 psi, in the range of 10 seconds / 500 ml to 19,000 seconds / 500 ml.

14. The porous membrane according to claim 13, characterized in that it has an absolute difference of no more than about 20% between the following: (i) The initial bubble point of the porous membrane, measured approximately 3 days before immersion in the solution, compared with... (ii) The initial bubble point of the porous membrane after it has been placed in the solution; The solution is (1) a 96% by weight sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and The initial bubble points mentioned in (i) and (ii) were measured at a temperature of about 22°C using ethoxy-nonafluorobutane HFE 7200.

15. A porous membrane comprising an aromatic fluoropolymer, said porous membrane being characterized by having an absolute difference of no more than about 20% among the following: (i) The initial bubble point of the porous membrane, measured not less than about 3 days before being placed in the solution, and (ii) The initial bubbling point of the porous membrane after being placed in the solution for no less than about 3 days; The solution is (1) a 96% by weight sulfuric acid solution, (2) a hot sulfuric acid solution, or (3) an SC1 solution; and The initial bubble points mentioned in (i) and (ii) were measured at a temperature of about 22°C using ethoxy-nonafluorobutane HFE 7200.

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