Poly(ionic liquid) composites for absorption and separation

Abstract

Provided herein are composites having expanded porous membranes and poly(ionic liquid)s (PILs), laminates and articles comprising the composites, and methods for making the composites, that exhibit excellent performance properties including high CO2 absorption, CO2 permeability, and CO2 / N2 selectivity, in combination with desirable mechanical properties such as being thin, strong, moisture and temperature resistant, flexible, strong, and durable.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Provisional Application No. 63 / 281,235, filed November 19, 2021, which is incorporated herein by reference in its entirety for all purposes.

[0002] The present disclosure generally relates to composites comprising expanded porous membranes and poly(ionic liquid)s (PILs), laminates and articles comprising the composites, and methods for making the composites, which have excellent performance properties including high CO2 absorption, high CO2 permeability, and CO2 / N2 selectivity, in combination with desirable mechanical properties (flexibility, strength, durability, etc.). [Background technology]

[0003] Ionic liquids (IOLs) are known as materials composed of cations and anions that exist as liquids at room temperature (<100°C) and ambient pressure. They have attracted attention for their specific properties, such as high thermal stability, high electrochemical stability, and low volatility, which distinguish them from known solvents. In general, IOLs can be tailored to have a variety of properties by appropriately selecting and combining cation and anion species. Ionic liquids are being investigated for various applications, including electrochemical devices, separation applications, and reaction solvents.

[0004] Polymerized ionic liquids, or poly(ionic liquids) (PILs), are the polymeric form of ionic liquids. Generally, ionic liquids are difficult to immobilize, and PIL membranes obtained directly from poly(ionic liquids), for example, by solvent casting, are brittle, difficult to handle, and can exhibit low CO2 permeability. While it is possible to impregnate ionic liquid monomers into porous polymer membrane supports, these structures tend to fracture under increased pressure, e.g., above 1-2 atmospheres, resulting in leakage or spurting of the ionic liquid.

[0005] Carbon dioxide has been identified as one of the major greenhouse gases, and it is widely accepted that CO2 emissions can affect the Earth's atmospheric ozone layer, depending on the atmospheric layer in which CO2 accumulates at that latitude. Excessive accumulation of CO2 in the atmosphere is believed to contribute to global warming. As a result, environmental and commercial efforts, with the cooperation of government agencies, have promoted the capture of CO2 from gas stream sources, such as power plant flue gas, for subsequent utilization or underground sequestration. A known method is to capture CO2 using amine solutions. However, CO2 captured with amine solutions can form carbamates or carboxylates, which, although reversible and reusable, undergo significant thermal or oxidative degradation, making their use less attractive.

[0006] Similarly, various polymeric membranes, especially CO2-selective membranes, have been developed to separate CO2 from mixed gases by selectively allowing CO2 to permeate. However, because polymeric membranes physically permeate CO2 based on a solution-diffusion mechanism, there are limitations to the improvements in CO2 permeability and CO2 / N2 selectivity that can be achieved. Furthermore, full-gas separation applications are considered harsh for most polymeric membranes, due to the high temperatures, high acidity, and high humidity.

[0007] Expanded porous membranes are known in the art. For example, expanded polytetrafluoroethylene (ePTFE) films can be produced by the process taught in U.S. Patent No. 3,953,566 to Gore. The porous ePTFE formed by this process has a microstructure of nodes interconnected by fibrils, exhibits greater strength than unexpanded PTFE, and retains the chemical inertness and wide useful temperature range of unexpanded PTFE. However, due to their porosity, such expanded PTFE membranes cannot be used alone as selective membranes.

[0008] Therefore, there is a need in the art for composite materials that exhibit improved performance, having a combination of desirable performance properties including high CO capture and separation, high CO / N selectivity, while at the same time possessing desirable mechanical properties such as thin, strong, and resistant to moisture, temperature, and chemicals. Summary of the Invention

[0009] Provided herein are composites comprising expanded porous membranes and poly(ionic liquid)s (PILs), laminates and articles comprising the composites, and processes for making the composites, which exhibit excellent performance properties including high CO2 absorption, permeability, and CO2 / N2 selectivity, combined with desirable mechanical properties such as thinness, strength, and resistance to moisture and temperature, and which have flexibility, strength, and durability.

[0010] Various aspects of the concepts addressed herein provide composites with superior CO2 absorption and separation properties without compromising the existing mechanical, chemical, and thermal properties of conventional porous membranes, sheets, or films. In some instances, the composites are made in unusual or surprisingly thin shapes, while in other instances the composites can be of substantial thickness.

[0011] According to a first embodiment ("Embodiment 1"), a composite material comprises an expanded porous membrane having a thickness, the expanded porous membrane having a microstructure consisting of fibrils and optionally nodes interconnecting the fibrils, and a void volume providing pores, and a poly(ionic liquid) polymer (PIL).

[0012] In addition to embodiment 1, according to a second embodiment ("embodiment 2"), the PIL forms a coating on the nodes and fibrils of the expanded porous membrane.

[0013] According to a third embodiment ("embodiment 3"), in addition to any of the previous embodiments, the PIL fills the entire void volume of the expanded porous membrane.

[0014] In addition to any of the previous embodiments, according to a fourth embodiment ("embodiment 4"), the PIL fills at least a portion of the void volume of the expanded porous membrane.

[0015] In addition to any of the previous embodiments, according to a fifth embodiment ("embodiment 5"), the PIL fills most of the void volume of the expanded porous membrane.

[0016] In addition to any of the preceding embodiments, according to a sixth embodiment ("Embodiment 6"), the expanded porous membrane comprises one or more of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), tetrafluoroethylene (TFE) copolymer, polylactic acid (PLA), polyparaxylylene (PPX), polyvinylidene difluoride (PVDF), vinylidene difluoride (VDF) copolymer, or poly(ethylenetetrafluoroethylene) (ETFE).

[0017] In addition to any of the previous embodiments, according to a seventh embodiment ("Embodiment 7"), the expanded porous membrane comprises expanded polytetrafluoroethylene (ePTFE) or expanded ultra-high molecular weight polyethylene (eUHMWPE).

[0018] In addition to any of the preceding embodiments, according to an eighth embodiment ("Embodiment 8"), the PIL comprises a cation selected from the group consisting of ammonium, imidazolium, pyridinium, phosphonium, and pyrrolidone, and a counteranion selected from the group consisting of halide, bistrifluoromethylsulfonimide, tetrafluoroborate, and acetate.

[0019] In addition to any of the preceding embodiments, according to a ninth embodiment ("Embodiment 9"), the PIL is selected from the group consisting of poly(diallyldimethylammonium) bis(trifluoromethane)sulfonimide (PDDMATFSI), poly(diallyldimethylammonium) chloride (PDDMACl), poly(diallyldimethylammonium) tetrafluoroborate (PDDMABF), poly((vinylbenzyl)trimethylammonium) bis(trifluoromethane)sulfonimide (PVBTMATFSI), poly((vinylbenzyl)trimethylammonium) chloride (PVBTMACl), poly((vinylbenzyl)trimethylammonium) tetrafluoroborate (PVBTMABF), and poly((vinylbenzyl)trimethylammonium) acetate (PVBTMAOAc).

[0020] According to a tenth embodiment ("Embodiment 10"), in addition to any of the previous embodiments, the composite material has a porosity of greater than about 20% and less than or equal to about 99%.

[0021] In addition to any of the previous embodiments, according to an eleventh embodiment ("Embodiment 11"), the composite material has a porosity of less than 20%.

[0022] In addition to any of the preceding embodiments, according to a twelfth embodiment ("Embodiment 12"), the composition further comprises at least one active agent.

[0023] In addition to embodiment 12, according to a thirteenth embodiment ("embodiment 13"), the active agent is covalently or non-covalently bound to the PIL.

[0024] According to a fourteenth embodiment ("Embodiment 14"), in addition to Embodiments 12 or 13, the active agent is selected from the group consisting of inorganic particles, inorganic nanoparticles, metals, metal oxides, metal salts, carbon nanotubes (CNTs), fullerenes, graphene, catalyst particles, polyoxometalates (POMs), metal-organic frameworks (MOFs), additional polymers, silica, quantum dots, ionic liquids, biologically active molecules, and any combination thereof.

[0025] In addition to embodiment 14, according to a fifteenth embodiment ("embodiment 15"), the biologically active molecule is a polypeptide, a protein, an enzyme catalyst, an enzyme, an enzyme extract, a whole cell, an antibody, a lipid, a nucleic acid molecule, a carbohydrate, or any combination thereof.

[0026] In addition to any of the preceding embodiments, according to a sixteenth embodiment ("Embodiment 16"), the weight percent of the poly(ionic liquid) polymer relative to the total weight of the composite material ranges from about 1 wt% to about 90 wt%.

[0027] In addition to any of the preceding embodiments, according to a seventeenth embodiment ("Embodiment 17"), the composite material further comprises a support layer.

[0028] According to an eighteenth embodiment ("Embodiment 18"), in addition to any of the preceding embodiments, the composite material has a CO2 absorption capacity of about 0.3 mmol CO2 / g PIL to about 1.2 mmol CO2 / g PIL.

[0029] According to a nineteenth embodiment ("Embodiment 19"), in addition to any of the preceding embodiments, the composite material has a CO2 permeability greater than 1.0 Barrer.

[0030] According to a twentieth embodiment ("Embodiment 20"), in addition to any of the preceding embodiments, the composite material has an N2 permeability of less than 1.5 Barrers.

[0031] According to a twenty-first embodiment ("Embodiment 21"), in addition to any of the preceding embodiments, the composite material has a selectivity, calculated as CO2 permeability / N2 permeability, greater than 8.0.

[0032] In addition to any of the previous embodiments, according to a twenty-second embodiment ("Embodiment 22"), there is provided a laminate comprising the composite material of any of the previous embodiments.

[0033] In addition to any of the previous embodiments, according to a twenty-third embodiment ("Embodiment 23"), there is provided an article comprising the composite of Embodiments 1-20 or the laminate of Embodiment 22.

[0034] In addition to any of the preceding embodiments, according to a twenty-fourth embodiment ("Embodiment 24"), a method for separating a gas from a mixture includes providing a composite material, laminate, or article of any of the preceding embodiments, and separating the gas from the mixture by contacting the mixture with the composite material, laminate, or article.

[0035] In addition to any of the preceding embodiments, according to a twenty-fifth embodiment ("Embodiment 25"), the gas is carbon dioxide.

[0036] In addition to any of the preceding embodiments, according to a twenty-sixth embodiment ("Embodiment 26"), the method further comprises: (a) dissolving a solid poly(ionic liquid) polymer in a solvent to form a poly(ionic liquid) polymer solution; (b) applying the poly(ionic liquid) polymer solution to a porous polymer membrane having a void volume providing pores and a microstructure consisting of nodes interconnected by fibrils or exclusively fibrils; and (c) applying the poly(ionic liquid) polymer solution to the porous polymer membrane followed by removing the solvent; Includes.

[0037] In addition to any of the preceding embodiments, according to a twenty-seventh embodiment ("Embodiment 27"), the poly(ionic liquid) polymer is partially or completely absorbed into the void volume of the microstructure of the porous polymer membrane.

[0038] In addition to embodiment 26 or 27, according to a twenty-eighth embodiment ("embodiment 28"), the method further comprises: (d) stretching the composite material after step (b) and / or after step (c).

[0039] In addition to embodiments 26 to 28, according to a twenty-ninth embodiment ("embodiment 29"), (f) after step (b), step (c) and / or step (d), further comprising compressing the composite material.

[0040] In addition to any of the preceding embodiments, according to a thirtieth embodiment ("Embodiment 30"), a method of forming the composite material includes: (a) providing (i) a poly(ionic liquid) polymer solution; and (ii) an expanded porous membrane having a first side and a second side, the expanded porous membrane having a microstructure consisting of fibrils and optionally nodes interconnecting the fibrils, and a void volume providing pores; (b) depositing the poly(ionic liquid) polymer solution on at least one side of the expanded porous membrane to form a composite material; and (c) optionally subjecting the composite material of step (b) to one or more steps of heating, stretching, compacting, or any combination thereof.

[0041] The foregoing embodiments are merely embodiments and should not be construed to limit or narrow the scope of the inventive concepts provided by the present disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. [Brief explanation of the drawings]

[0042] The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments and, together with the description, serve to explain the principles of the disclosure.

[0043] [Figure 1] FIG. 1 is an SEM micrograph of a cross-sectional sample of a PIL-fully imbibed ePTFE membrane including a monolithic top coating, according to one embodiment.

[0044] [Figure 2] FIG. 2 is an SEM micrograph of a cross section of a PIL-coated sample analyzed by EDS (energy dispersive X-ray spectroscopy) imaging, showing the PIL coating on the nodes and fibrils of the ePTFE membrane.

[0045] [Figure 3] Figures 3A and 3B are graphical images of the kinetic data and temperature swing sorption cycles measured in Example 6. Figure 3A represents data collected for an ePTFE-poly((vinylbenzyl)trimethylammonium) acetate (PVBTMAOAc) ​​membrane composite, while Figure 3B represents data collected for a PVBTMAOAc powder. DETAILED DESCRIPTION OF THE INVENTION

[0046] Definitions and Terminology This disclosure is not intended to be read in a restrictive manner, for example, the terms used in this application should be read broadly in the context of the meaning that would be ascribed to such terms by a specialist in the field.

[0047] With respect to the term imprecision, the terms "about" and "approximately" may be used interchangeably to refer to a measurement, including the stated measurement and any measurement reasonably close to the stated measurement. A measurement reasonably close to the stated measurement deviates from the stated measurement by a reasonably small amount, as understood and easily ascertained by one of ordinary skill in the relevant art. Such deviations may result from measurement errors, differences in calibration of measuring and / or manufacturing equipment, human error in reading and / or setting measurements, fine-tuning made to optimize performance and / or structural parameters to account for differences in measurements associated with other components, specific implementation scenarios, imprecise adjustment and / or manipulation of objects by humans or machines, and the like. If it is determined that the value of such a reasonably small difference would not be easily ascertainable by one of ordinary skill in the relevant art, the terms "about" and "approximately" may be understood to mean plus or minus 10% of the stated value.

[0048] Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each range are significant both in relation to the other endpoint and independently of the other endpoint. When ranges are recited in the specification and claims, they are understood to include all numbers within that range, including fractional numbers, whether or not specifically disclosed. For example, if the range is 1 to 10, the range includes all the numbers in that range, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, The ranges include 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, and 10. It is further understood that unless otherwise specified, "0" is not included in the ranges below, and similarly, unless otherwise specified, "100" is not included in the ranges above.

[0049] As used in this application, the term "pore size" refers to the average size of the pores in a porous membrane. Pore size can be characterized by bubble point, mean flow pore size, or water entry pressure, as described in more detail herein.

[0050] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, the term "on" is intended to indicate that when an element is "on" another element, it may be directly on the other element, or there may be intervening elements present. It should be understood that the terms "fine powder" and "powder" may be used interchangeably herein. Also, the terms "ePTFE membrane" and "membrane" may be used interchangeably herein. Furthermore, in this application, the term "ePTFE membrane" is intended to include single-layer or multi-layer ePTFE membranes. It should be understood that the machine direction and longitudinal direction are the same and may be used interchangeably herein. Furthermore, the terms "microporous ePTFE membrane" and "ePTFE membrane" may be used interchangeably herein.

[0051] The PTFE starting material can be a PTFE homopolymer, a modified PTFE homopolymer, or a blend of PTFE homopolymers. In another embodiment, the PTFE starting material can be a blend of a PTFE homopolymer and a PTFE copolymer in which the comonomer units are not present in an amount that would cause the copolymer to lose the non-melt-processible properties of pure homopolymer PTFE. Examples of suitable comonomers in PTFE copolymers include, but are not limited to, olefins such as ethylene and propylene, halogenated olefins such as hexafluoropropylene (HFP), vinylidene fluoride (VDF) and chlorofluoroethylene (CFE), and perfluoroalkyl vinyl ethers (PPVE) and perfluorosulfonyl vinyl ethers (PSVE). In yet another embodiment, the first PTFE membrane and / or the second PTFE membrane can be formed from a blend of a high molecular weight PTFE homopolymer and a low molecular weight modified PTFE polymer.

[0052] Description of Various Embodiments Those skilled in the art will readily appreciate that the various aspects of the present disclosure may be implemented by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying drawings referred to herein are not necessarily drawn to scale and may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawings should not be construed as limiting.

[0053] Various concepts discussed herein relate to composite materials comprising expanded porous membranes and poly(ionic liquids). This description also provides methods for making the composite materials. The composite materials can combine desirable mechanical properties, such as one or more of relatively high flexibility, strength, and durability, with excellent performance properties, including one or more of very high CO2 absorption capacity, high CO2 / N2, and CO2 / CH4 selectivity.

[0054] A composite material according to one embodiment includes a porous membrane and a poly(ionic liquid) polymer (PIL). It should be readily understood that multiple types of porous membranes and multiple types of PILs can be combined within the spirit of this embodiment. The porous membrane of this embodiment can have any suitable microstructure to achieve the desired composite performance. For example, the porous membrane can have a microstructure of substantially only fibrils, or optionally nodes interconnecting the fibrils, and void volume providing pores. Porous PTFE membranes can be prepared using methods known to those skilled in the art, such as those described in U.S. Patent No. 3,953,566 to Gore, U.S. Patent No. 5,814,405 to Branca, U.S. Patent No. 7,306,729 to Bacino, and U.S. Patent No. 5,476,589 to Bacino.

[0055] In one embodiment, the porous membrane can have a substantially fibril microstructure, as generally taught in U.S. Patent No. 7,306,729 to Bacino. An expanded porous membrane having substantially fibril microstructure, as shown, can be, for example, about 20 mm thick.2 / g or more than 25m 2 / g, and in some embodiments, at least 1.5×10 5 MPa 2 and / or a ratio of the matrix tensile strengths in two orthogonal directions of less than 2, and in some cases less than 1.5, can provide a material with highly balanced strength. According to embodiments, the expanded porous membrane is expected to have a mean flow pore size of less than about 5 μm, less than about 1 μm, and less than about 0.10 μm. It is expected that the expanded porous membrane can have substantially all fibrils with a diameter of less than about 1 μm.

[0056] In another embodiment, the expanded fluoropolymer can have a microstructure of nodes interconnected by fibrils, as described in U.S. Patent No. 3,953,566 to Gore. The fibrils extend from the nodes in multiple directions, and the membrane has a substantially homogeneous structure. For example, the microstructure can exhibit a ratio of matrix tensile strength in two orthogonal directions of less than 2, or even less than 1.5, although it will be understood that other ratios are equally suitable. Furthermore, the expanded fluoropolymer membrane, according to some embodiments, can have a mean flow pore size of less than about 5 μm, less than about 1 μm, and less than about 0.10 μm. In some embodiments, the expanded fluoropolymer membrane can have fibrils in a node-fibril structure with diameters of less than about 1 μm. In yet other embodiments, the expanded fluoropolymer membrane can have a microstructure of substantially all fibrils with diameters of less than about 1 μm.

[0057] Non-limiting examples of suitable synthetic polymer membranes include polyurethane, polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), polyvinylidene fluoride (PVDF), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkanes (PFA), modified polytetrafluoroethylene polymers, tetrafluoroethylene (TFE) copolymers, polyalkylenes such as polypropylene and polyethylene, polyestersulfones (PES), polyesters, porous poly(p-xylylene) (ePPX) as taught in U.S. Patent Publication No. 2016 / 0032069, U.S. Patent ... No. 9,932,429 to Sbriglia; porous polylactic acid (ePLLA) as taught in U.S. Patent No. 7,932,184 to Sbriglia et al.; porous vinylidene fluoride-co-tetrafluoroethylene or trifluoroethylene [VDF-co-(TFE or TrFE)] polymers as taught in U.S. Patent No. 9,441,088 to Sbriglia; and copolymers and combinations thereof. In at least one embodiment, the synthetic polymer membrane is a microporous synthetic polymer membrane, such as a microporous fluoropolymer membrane having a node-and-fibril microstructure, where the nodes are interconnected by fibrils and the pores are voids or spaces located between the nodes and fibrils throughout the membrane. An exemplary node and fibril microstructure is described in US Pat. No. 3,953,566 to Gore.

[0058] In some embodiments, the porous membrane may include one or more of the following: polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), tetrafluoroethylene (TFE) copolymer, polylactic acid (PLA), polyparaxylylene (PPX), polyvinylidene difluoride (PVDF), vinylidene difluoride (VDF) copolymer, poly(ethylenetetrafluoroethylene) (ETFE), and combinations thereof.

[0059] In one preferred embodiment, the composite material can include an expanded porous membrane made from expanded polytetrafluoroethylene (ePTFE) or expanded ultra-high molecular weight polyethylene (eUHMWPE), as generally described, for example, in U.S. Pat. No. 7,306,729. Expanded ePTFE can include PTFE homopolymer. In alternative embodiments, blends of PTFE, expandable modified PTFE, and / or expanded copolymers of PTFE can be used. Non-limiting examples of suitable fluoropolymer materials are described, for example, in U.S. Pat. No. 4,576,869 to Malhotra, U.S. Pat. Nos. 5,814,405 and 5,708,044 to Branca, U.S. Pat. No. 6,541,589 to Baillie, U.S. Pat. No. 7,531,611 to Sabol, U.S. Pat. No. 8,637,144 to Ford, and U.S. Pat. No. 9,139,669 to Xu.

[0060] The porous membrane according to the embodiment has a PTFE density of about 2.18 g / cm 3 Based on this, the matrix tensile strength can range from about 50 MPa to about 2000 MPa or more.

[0061] The porous membrane of this embodiment can be tailored to have any suitable thickness and weight to achieve the desired composite performance. In some cases, it may be desirable to use a very thin expanded porous membrane having a thickness of less than about 10.0 μm. In other embodiments, it may be desirable to use an expanded porous membrane having a thickness of greater than about 15 μm and less than about 250 μm. The expanded porous membrane may have a thickness of about 5 g / m 2 Less than to about 200 g / m 2 The specific gravity may be greater than 1.

[0062] Several types of PILs that can be included in the composite material include PILs whose cations are selected from the group consisting of ammonium, imidazolium, pyridinium, phosphonium, and pyrrolidone, and whose counter anions are selected from the group consisting of halides, bistrifluoromethylsulfonimides, tetrafluoroborate, and acetate. The counter anions can also be poly(anions).

[0063] In some embodiments, for example, the PIL can include poly(diallyldimethylammonium) bis(trifluoromethane)sulfonimide (PDDMATFSI), poly(diallyldimethylammonium) chloride (PDDMACl), poly(diallyldimethylammonium) tetrafluoroborate (PDDMABF), poly((vinylbenzyl) trimethylammonium) bis(trifluoromethane)sulfonimide (PVBTMATFSI), poly((vinylbenzyl) trimethylammonium) chloride (PVBTMACl), poly((vinylbenzyl) trimethylammonium) tetrafluoroborate (PVBTMABF), or poly((vinylbenzyl) trimethylammonium) acetate (PVBTMAOAc).

[0064] In one embodiment, the PIL occupies substantially all of the void volume or space within the porous structure of the stretched porous membrane. Alternatively, the PIL can partially fill the void volume of the stretched porous membrane, or the PIL can fill the entire void volume, i.e., 100%, which can also be referred to as fully filled. In another embodiment, the PIL is present in substantially all or a portion of the pores of the stretched porous membrane. In yet another embodiment, the PIL can form a coating on the nodes and fibrils of the stretched porous membrane. For example, the PIL can fill at least a portion of the void volume of the stretched porous membrane, where a portion may be defined as about 10%, about 20%, about 30%, about 40%, or about 50%. Alternatively, the PIL can fill a majority of the void volume of the stretched porous membrane, where "majority" may be defined as about 50%, about 60%, about 70%, about 80%, or about 90%.

[0065] In further embodiments, the composite material can have a porosity of greater than about 20%, greater than about 30%, greater than about 40%, greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, or greater than about 90%. The composite material can have a porosity of less than about 95%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, or less than about 20%. The composite material can have a porosity ranging from greater than about 20% to about 90%, or any porosity within these endpoints. It should also be readily understood that too little porosity can result in reduced gas permeability.

[0066] The porous membrane can have a void volume that provides the pores. The pores can have an average diameter ranging from about 0.001 μm to about 10 μm, or any of the endpoints therein.

[0067] Additional materials can be incorporated into the pores, within the composite, or between layers of a laminate containing the composite to enhance or tailor desired properties of the composite or laminate. In one embodiment, the composite can include at least one active agent. The active agent can be covalently or non-covalently bound to the PIL. Examples of active agents include inorganic particles, inorganic nanoparticles, metals, metal oxides, metal salts, carbon nanotubes (CNTs), fullerenes, graphene, catalyst particles, polyoxometalates (POMs), metal-organic frameworks (MOFs), additional polymers, silica, quantum dots, ionic liquids, and biologically active molecules.

[0068] Biologically active molecules can include, for example, polypeptides, proteins, enzyme catalysts, enzymes, enzyme extracts, whole cells, antibodies, lipids, nucleic acid molecules, or carbohydrates.

[0069] The weight percent of the PIL polymer relative to the total weight of the composite can range from 1 wt % to 90 wt % in any embodiment, or the weight percent of the PIL polymer relative to the total weight of the composite can be any percentage between these endpoints.

[0070] Composite materials or laminates according to embodiments of the present invention can be utilized as CO separation membranes, where the composite materials exhibit high CO permeability and CO / N selectivity. For example, the composite materials can have a CO permeability of greater than 1.0 barrer, or greater than 2.0 barrer, or greater than 3.0 barrer, or greater than 4.0 barrer, or greater than 5.0 barrer, or greater than 6.0 barrer, or greater than 7.0 barrer, or greater than 8.0 barrer, or greater than 9.0 barrer, or greater than 9.5 barrer, or greater than 10.0 barrer, where 1.0 barrer is 3.35×10 -16 mole m / (s m 2·Pa). Similarly, the composite material can have an N2 permeability of less than 1.5 barrer, less than 1.3 barrer, or less than 1.1 barrer. In some embodiments, the composite material can have a CO2 permeability of about 1.0 barrer to about 4.0 barrer, or about 1.0 barrer to about 3.0 barrer, or about 1.0 barrer to about 2.0 barrer, or about 1.0 barrer to about 1.5 barrer, or about 1.0 barrer to about 1.4 barrer, or about 1.0 barrer to about 1.3 barrer, or about 1.0 barrer to about 1.2 barrer, or about 1.0 barrer to about 1.1 barrer, or any value included between these endpoints. The composite material can have a selectivity, calculated as CO2 permeability / N2 permeability, of greater than 8.0, greater than 9.0, or greater than 10.0.

[0071] Similarly, composites or laminates according to embodiments of the invention can have high CO2 absorption capacities. Composite films can have higher absorption per mass of PIL in the composite than in PIL powder. For example, composites can have CO2 absorption capacities of greater than 0.3 mmol CO2 / g PIL, greater than 0.4 mmol CO2 / g PIL, greater than 0.5 mmol CO2 / g PIL, greater than 0.6 mmol CO2 / g PIL, 0.7 mmol CO2 / g PIL, greater than 0.8 mmol CO2 / g PIL, greater than 0.9 mmol CO2 / g PIL, greater than 1.0 mmol CO2 / g PIL, greater than 1.5 mmol CO2 / g PIL, or greater than 2.0 mmol CO2 / g PIL. Composites can have CO2 absorption capacities of between about 0.3 mmol CO2 / g PIL and about 2.0 mmol CO2 / g PIL.

[0072] In some embodiments, the composite material is thin and can have a thickness of less than about 1000 μm (1.0 mm), less than about 500 μm, less than about 100 μm, less than about 50 μm, less than about 10 μm, less than about 1 μm, less than about 0.5 μm, or less than about 0.1 μm, or less than about 0.05 μm. For example, the composite material can have a thickness of about 0.04 μm to about 1.0 mm, or any value within this range.

[0073] The composite material can include a substrate or support layer to which it can be laminated, glued, or otherwise bonded (e.g., thermally, mechanically, or chemically). Non-limiting examples of suitable substrates or support layers include, but are not limited to, fluorinated ethylene propylene (FEP), perfluoroalkoxyalkanes (PFA), polytetrafluoroethylene (PTFE), terpolymers of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride (THV), polyurethane, polyamide, ethylene vinyl alcohol (EVOH), and polyvinyl chloride (PVC). The substrate can also be a metal sheet, an inorganic sheet, or a pressure-sensitive adhesive. Such laminated structures can facilitate or enhance further bonding to additional layers, such as textiles. The substrate or support layer can include a textile layer, including knitted, woven, or nonwoven materials.

[0074] A laminate including a composite material can have one or more layers, such as two or three or more layers, hi one embodiment, the composite material can be disposed between a first layer and a second layer.

[0075] Articles or laminates comprising the composite materials can exhibit excellent absorbency and mechanical properties. Articles comprising the composite materials can be in the form of sheets, tubes, or free-standing three-dimensional shapes. Alternatively, the articles can be included in laminates or composites. The composite materials, articles, or laminates can be used for direct air capture for CO2 sequestration, gas absorption from fluid streams, CO2 capture and separation in power plant flue gases, as CO2 sensors, or in applications requiring CO2 / N2 or CO2 / CH4 separation.

[0076] As described above, the PIL is combined with the stretched porous membrane such that the PIL partially or substantially completely fills the void volume or pores within the stretched porous membrane. This filling of the pores of the stretched porous membrane with the PIL can be accomplished by various methods, such as absorption by a drawdown bar, wire bar, gravure rolling, or spin coating. In one embodiment, a method for filling the pores of a stretched porous membrane includes dissolving a poly(ionic liquid) in a suitable solvent to produce a solution with a viscosity and surface tension suitable to flow partially or completely into the pores of the stretched porous membrane, and evaporating the solvent to leave behind the PIL.

[0077] In various embodiments, the composite material can include an absorbent zone and a non-absorbent zone, and the absorbent zone can be formed, for example, by imbibing a PIL into a portion of the porous membrane. Such an absorbent zone can be formed, for example, by "butter coating" or slot die coating.

[0078] In one embodiment, a method for forming a composite material includes dissolving a solid PIL polymer in a solvent to form a PIL polymer solution, applying the PIL polymer solution to a porous polymer membrane having a void volume providing pores and a microstructure of nodes interconnected by fibrils or a microstructure of only fibrils, and removing the solvent after applying the PIL polymer solution to the porous polymer membrane. The PIL polymer can be partially or completely absorbed into the void volume of the microstructure of the porous polymer membrane.

[0079] In another embodiment, a method for forming a composite material can include spin coating. For example, a composite material can be formed by providing a PIL polymer solution and an expanded porous membrane having a first side and a second side, wherein the expanded porous membrane has a void volume and a microstructure of fibrils that provide pores, and optionally a microstructure of nodes that interconnect the fibrils, and spinning the PIL solution onto the membrane, whereby the PIL polymer solution is deposited on at least one side of the expanded porous membrane, thereby forming a composite material.

[0080] It should be readily understood that additional processing steps are within the scope of the present embodiments. The additional processing can optionally include subjecting the composite material to one or more of the following steps: heating, stretching, compressing, compacting, or any combination thereof. For example, the composite material can be stretched after applying the PIL polymer solution to the porous polymer, or after applying the PIL polymer solution and removing the solvent, or after each of these process steps. In other embodiments, the composite material can be compressed after applying the PIL polymer solution to the porous polymer, or after applying the PIL polymer solution and removing the solvent, or after stretching the composite material, or after each of these process steps. The inventors have discovered that the combination of these unique processing capabilities allows for the manipulation of the ePTFE pore structure, porosity, and density of the composite membrane, which in turn allows for optimization of permeability and selectivity while providing adequate support for the fragile PIL membrane.

[0081] In summary, composite materials prepared by the methods provided herein, and articles or laminates comprising the composite materials, exhibit a combination of desirable absorption properties, including high CO permeability and CO / N selectivity, and highly desirable mechanical properties, including flexibility, strength, and durability. The methods presented herein provide support for the fragile PIL membrane, while allowing for optimization of permeability and selectivity through unique processing capabilities for manipulating the ePTFE pore structure, porosity, and density of the composite membrane. [Example]

[0082] Test Method Although particular methods and apparatus are described below, it should be understood that other methods or apparatus may alternatively be used as deemed suitable by those skilled in the art.

[0083] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The concept of the present invention is further defined in the following examples. It should be understood that these examples, while showing preferred embodiments of the present invention, are given for illustrative purposes only. From the above discussion and these examples, those skilled in the art can ascertain the essential features of some embodiments, and can make various changes and modifications to adapt the concept of the present invention to various applications and conditions without departing from the spirit and scope thereof. Thermogravimetric analysis (TGA) Thermogravimetric sorption data were collected using a Discovery TGA 5500 thermogravimetric analyzer from TA Instruments (New Castle, Del.) Carbon dioxide and helium were plumbed into the thermogravimetric analyzer. CO2 sorption method 1 CO2 Sorption Method 1 utilized the following process steps: Programming process Description 1. Gas Selection 1 Purge with helium at 25 mL / min. 2. Ramp to 70°C at 20°C / min. Heat to 70°C for degassing. 3. Isothermal for 300 minutes. Degas for 5 hours. 4. Ramp to 30°C at 20°C / min. Cool to 30°C for sorption analysis. 5. Isothermal for 30 minutes. Allow the temperature to stabilize. 6. Gas Selection 2 Purge with CO2 at 25 mL / min. 7. Measure mass uptake during isothermal adsorption for 60 minutes. 8. Gas Selection 1 Purge with helium at 25 mL / min. 9. Measure the mass loss during isothermal desorption for 60 minutes. 10. Repeat steps 6 to 9 three times. Repeat the cycle three times and evaluate the reproducibility. CO2 sorption method 2 CO2 Sorption Method 2 for measuring adsorption / desorption kinetics utilized the following process steps: Programming process Description 1. Data Storage On 2. Gas Selection 1 Purge with helium at 25 mL / min. 3. Ramp to 100°C at 10°C / min. Heat to 100°C for degassing. 4. Isothermal for 120 minutes. Degas for 2 hours. 5. Ramp to 30°C at 10°C / min. Cool to 30°C for sorption analysis. 6. Isothermal for 30 minutes. Allow the temperature to stabilize. 7. Gas Selection 2 Purge with CO2 at 25 mL / min. 8. Measure mass uptake during isothermal adsorption for 480 min. 9. Gas Selection 1 Purge with helium at 25 mL / min. 10. Ramp to 100°C at 10°C / min for desorption analysis. 11. Measure the mass loss during isothermal desorption for 120 minutes. 12. Data Storage Off 13. Ramp to 30°C at 10°C / min CO2 Sorption Method 3 (Temperature Swing Absorption / Desorption Cycle, TSA) CO2 sorption method 3 utilizes the following steps: Programming process Description 1. Data Storage On 2. Gas 1: N2 Purge with nitrogen at 90 mL / min for 2 hours. 3. Ramp to 100°C at 10°C / min. Heat to 100°C for degassing. 4. Isothermal for 120 minutes. Degas for 2 hours. 5. Ramp to 30°C at 10°C / min. Cool to 30°C for sorption analysis. 6. Isothermal for 30 minutes. Allow the temperature to stabilize. 7. Gas 2: Purge CO2 at 90 mL / min. 8. Measure mass uptake during isothermal adsorption for 60 minutes. 11. Gas 1: N2 Purge with nitrogen at 90 mL / min. 12. Ramp to 100°C at 10°C / min for desorption analysis. 13. Measure the mass loss during isothermal desorption for 30 minutes. 14. Repeat sequence 6-13 10 times 15. Data Storage Off 16. Ramp to 30°C at 10°C / min

[0084] ATEQ Airflow ATEQ Airflow is a test method for measuring the laminar volumetric flow rate of air through a membrane sample. For each membrane, a 2.99 cm diameter airflow across the flow channel is measured. 2 The samples were clamped between two plates to seal the area of ​​The air flow rate (L / hr) through each membrane sample was measured using an ATEQ® (ATEQ Corp., Livonia, MI) Premier D Compact Flow Tester by imposing an air flow at a differential pressure of 1.2 kPa (12 mbar) across the membrane.

[0085] Bubble Point Bubble point pressure was measured using a capillary flow porometer (Model 3Gzh, Quantachrome Instruments, Boynton Beach, Florida) according to the general teachings of ASTM F31 6-03. The sample membrane was placed in the sample chamber and wetted with Silwick Silicone Fluid (available from Porous Materials Inc.) with a surface tension of 20.1 dynes / cm. The bottom clamp of the sample chamber, equipped with a 2.54 cm diameter, 0.159 cm thick porous metal disc insert (Quantachrome Part No. 75461 Stainless Steel Filter), was used to support the sample. Using 3GWin software version 2.1, the following parameters were set as specified in the table immediately below. The value shown for bubble point pressure is the average of two measurements. The bubble point pressure was converted to pore size using the following equation:

number

[0086] Thickness measurement (contact with snap gauge) The thickness of the membrane was measured by placing the membrane between the two plates of a Kafer FZ1000 / 30 thickness snap gauge (Kafer Messuhrenfabrik GmbH, Villingen-Schwenningen, Germany). The average of three measurements was used.

[0087] The thickness of the laminate was measured by placing the film between the two plates of a Mitutoyo Tektronix snap gauge (part number 547-400S).

[0088] Mass per area (mass / area) The mass per area of ​​the samples was measured according to ASTM D 3776 (Standard Test Method for Mass (Weight) per Unit Area of ​​Fabrics) Test Method (Option C) using a Mettler Toledo Scale, Model 1060. The scale was recalibrated before weighing the specimens, and the results were reported in grams per square meter (g / m).

[0089] Measurement of matrix tensile strength The membranes were cut in both the longitudinal and transverse directions using an ASTM D412-Dog Bone Die Type F (D412F). The "machine direction" is the direction of extrusion and the "transverse direction" is perpendicular thereto. Once the dog bone samples were prepared, they were weighed to determine the mass of the samples using a Mettler Toledo scale, Model AG204.

[0090] The tensile break load was measured using an INSTRON® 5500R (Illinois Tool Works Inc., Norwood, MA) tensile tester equipped with a rubber-coated faceplate and a serrated faceplate, with each end of the sample held between one rubber-coated faceplate and one serrated faceplate. The pressure applied to the grip plates was approximately 552 kPa. The gauge length between the grips was set to 58.9 mm, and the crosshead speed (pulling rate) was set to 508 mm / min. A 500 N load cell was used to perform these measurements, and data were collected at a rate of 50 points / sec. The laboratory temperature was maintained between 20 and 22.2°C to ensure comparable results. If the sample failed at the grip interface, data were discarded. To characterize the samples, at least three samples in the machine direction and three samples in the transverse direction were successfully pulled (without slipping out of the grips or breaking in the grips).

[0091] The matrix tensile strength (MTS) was calculated using the following formula:

[0092]

number

[0093] In the above formula, F is the maximum load in the test, and A is the x cross-sectional area of ​​the PTFE. The x cross-sectional area of ​​the PTFE is not the same as the x cross-sectional area of ​​the test specimen due to potential pores / defects in the sample. The x cross-sectional area of ​​the PTFE can be calculated as follows:

[0094]

number

[0095] example Expanded polytetrafluoroethylene (ePTFE) membrane The present invention can utilize various porous PTFE membranes known in the art, based on the teachings of U.S. Patents 4,576,869 to Malhotra, 5,814,405 to Branca, and 5,708,044 to Branca, using different PTFE fine powders or fine powder mixtures, or modified PTFE resin powders such as those described in U.S. Patents 6,541,589 to Baillie, 7,531,611 to Sabol, 8,637,144 to Ford, and 9,139,669 to Xu. The PTFE fine powders can be fabricated into membranes using processing methods known to those skilled in the art, such as those described in U.S. Patents 3,953,566 to Gore, 5,814,405 to Branca, 7,306,729 to Bacino, and 5,476,589 to Bacino.

[0096] ePTFE membrane type A Membrane Type A was prepared using a fine powder of high molecular weight PTFE polymer produced by the process described in Malhotra, U.S. Patent No. 4,576,869, and the resulting properties are shown in Table 1.

[0097] ePTFE membrane type B Membrane Type B was fabricated by applying a hydrophilic polymer coating (ethylene-vinyl alcohol copolymer; EVOH) to an expanded ePTFE membrane (ePTFE membrane Type A, fabricated as described above). Briefly, a 2 wt% coating solution was prepared by dissolving SOARANOL® EVOH (Mitsubishi Chemical Corporation, Tokyo, Japan; product number DT2904; ethylene content approximately 29 mol%) in a mixture of ethanol and water. The coating solution was applied to the ePTFE membrane using a wire bar at a speed of 1 meter / min at room temperature (approximately 22 °C) and then dried at 70 °C in a continuous process. The coated ePTFE membrane was hydrophilic and readily wettable. The resulting properties are shown in Table 1.

[0098] ePTFE membrane type C Membrane Type C was prepared using a fine powder of high molecular weight PTFE polymer produced by the process described in Malhotra, U.S. Patent No. 4,576,869. The resulting properties are shown in Table 1.

[0099] ePTFE membrane type D Membrane Type D was prepared using a fine powder PTFE blend (about 50 wt. % PTFE homopolymer and about 50 wt. % modified PTFE resin) as described in Example 1 of U.S. Patent No. 5,814,405 to Branca, and the resulting properties are shown in Table 1. [Table 2]

[0100] Poly(ionic liquid) The following abbreviations are used herein: PDDMA = poly(diallyldimethylammonium), PVBTMA = poly((vinylbenzyl)trimethylammonium), TFSI = bis(trifluoromethane)sulfonimide, Cl = chloride, BF = tetrafluoroborate, OAc = acetate. Poly(ionic liquids) were obtained from the following vendors: PDDMACl was obtained from Sigma-Aldrich (product number 409022, CAS number 26062-79-3, Mw = 200,000-350,000 g / mol), and PVBTMACl was obtained from Scientific Polymer Products Inc. (catalog number 879, CAS No. 9017-80-5, Mw = 400,000 g / mol). The others were prepared as described below. Conversion between different poly(ionic liquids) is accomplished via a metathesis-type reaction starting from the chloride form of the poly(ionic liquid) (see Example 1). [Table 3]

[0101] Example 1 Conversion of PDDMAC1 to PDDMATFSI Approximately 200 grams of lithium bis(trifluoromethane)sulfonimide (LiTFSI) was mixed with 1.5 L of water (RO, reverse osmosis, HO) in a 3-liter beaker equipped with a mechanical stirrer. The mixture was stirred at room temperature (approximately 22°C). A solution of PDDMACl (500 grams of a 20 wt% aqueous solution) was mixed with an additional 1 L of water. This solution was placed in an addition funnel (1500 mL). The aqueous PDDMACl solution was then added dropwise to the aqueous LiTFSI solution with stirring. The resulting mixture contained LiCl dissolved in the water and a precipitate of PDDMATFSI. The PDDMATFSI solid was filtered and washed with 3 L of water for 30 minutes. This process was repeated three times. The precipitate was filtered and then dried at 60°C for 4 hours, followed by drying at 100°C overnight. The resulting yield was 48.27%.

[0102] Example 2 Preparation of composite membranes Poly(ionic liquid) (PIL) was dissolved in an appropriate solvent to a target concentration ranging from 2 wt% to 20 wt%, depending on the poly(ionic liquid) / solvent combination. The resulting solution was applied to an expanded polytetrafluoroethylene (ePTFE) membrane confined in a hoop. The solution was spread over the surface of the confined membrane until the membrane was completely coated. The solution-coated ePTFE membrane was then dried in air at room temperature (approximately 22 °C) or in a drying oven at 70–120 °C for approximately 5 minutes. This typically results in a membrane coated with nodal fibrils (NF). Fully imbibed (FI) composite membranes were prepared by additional rounds of coating / drying and / or the use of a more concentrated imbibition solution.

[0103] [Table 4]

[0104] Example 3 Preparation of the Laminate Various multilayer laminates were prepared by bonding at least one composite membrane from Example 2 to another composite membrane and / or at least one reinforcing layer. Two or more layers were compressed together using a two-roller compactor with a force of 400 N / mm at a speed of 1 m / min. The properties of the resulting laminates are shown in Table 4. Other compression methods can also be implemented, such as stacking the layers in a hydraulic hand press and pressing the layers together while applying heat to form the final laminate. Another composite utilizing a densified PTFE film as the outer layer was prepared in the same manner as the composite utilizing an ePTFE membrane. [Table 5]

[0105] Example 4 CO2 absorption analysis Test samples of PIL powder or composite films were placed in a thermogravimetric analyzer (TGA) system for CO2 absorption analysis, as described in CO2 Sorption Method 1. The test begins by degassing the sample at 70°C or 120°C for 5 hours. The degassed sample is then cooled to 30°C, and carbon dioxide (CO2) gas (100% at 30°C) is then introduced into the system. The amount of absorbed CO2 is determined by the weight increase of the sample over 60 minutes or until saturation (maximum weight) is reached. The atmosphere in the system is then replaced with helium, allowing the CO2 absorbed by the test sample to desorb. The weight decreases, and then a minimum weight is established after approximately 60 minutes. The difference between the maximum and minimum values ​​is taken as the working capacity, which can be converted to millimoles of CO2 per gram of poly(ionic liquid) (mmol / g). The absorption results are shown in Table 5 (PIL powder degassed at 70°C), Table 6 (PIL powder degassed at 120°C), Table 7 (ePTFE composite degassed at 70°C), and Table 8 (ePTFE composite degassed at 120°C). [Table 6] [Table 7] [Table 8] [Table 9]

[0106] In Tables 7 and 8, NF refers to node and fibril coating, BC refers to butter coating, and FI refers to full absorption.

[0107] Example 5 CO2 vs. N2 permselectivity analysis Permeability testing was performed using a Lab Think Perme Vac V2 permeability tester according to ASTM method D1434. Samples were tested by inserting the film into the tester and selecting a single gas (CO2). After the test was completed, another gas (N2) was selected and tested on the same sample. The gas transmission rate (GTR) was then normalized by thickness to calculate the permeability coefficient for each film.

[0108] Selectivity is calculated as the ratio of CO2 permeability to N2 permeability for a given composite membrane.

[0109] The three-layer laminate was constructed and compressed as described in Example 3. The control was a three-layer laminate without imbibed PIL, containing only three layers of ePTFE membrane, also compressed as described in Example 3. [Table 10] Example 6 Dynamic adsorption and desorption of CO2 The kinetic adsorption / desorption of CO was measured using CO2 Sorption Method 2. Kinetic data were measured for both the composite ePTFE PVBTMAOAc membrane (Sample 4 in Table 7) and the PVBTMAOAc powder (Sample 4 in Table 5). The data were collected and plotted in Figures 3A and 3B. The line plot represents the kinetic curve recorded for 8 hours of continuous CO2 adsorption (100% CO2, 30 °C). The bars in Figures 3A and 3B represent the CO2 uptake recorded in each cycle under temperature swing adsorption-desorption cycling according to CO2 sorption method 3 (10 cycles, conditions: all samples were isothermally heated at 100 °C for 2 h under N2 flow in a TGA (method 3 step 4) for degassing). Adsorption: 30 °C, 100% CO2 for 1 h; Desorption: 100 °C, 100% N2 for 30 min. The flow rate for the two series of experiments was 90 mL / min. All experiments were performed under dry conditions.

Claims

1. An expanded porous membrane having a thickness comprising expanded polytetrafluoroethylene (ePTFE) or expanded ultra-high molecular weight polyethylene (eUHMWPE), the expanded porous membrane having a microstructure consisting of fibrils and optionally nodes interconnecting the fibrils, and a void volume providing pores; and a poly(ionic liquid) polymer (PIL), wherein the PIL is selected from the group consisting of poly(diallyldimethylammonium)bis(trifluoromethane)sulfonimide (PDDMATFSI), poly(diallyldimethylammonium)chloride (PDDMACl), poly(diallyldimethylammonium)tetrafluoroborate (PDDMABF4), poly((vinylbenzyl)trimethylammonium)bis(trifluoromethane)sulfonimide (PVBTMATFSI), poly((vinylbenzyl)trimethylammonium)chloride (PVBTMACl), poly((vinylbenzyl)trimethylammonium)tetrafluoroborate (PVBTMABF4), and poly((vinylbenzyl)trimethylammonium)acetate (PVBTMAOAc).

2. The composite material of claim 1 , wherein the PIL forms a coating on the nodes and fibrils of the expanded porous membrane.

3. 3. The composite of claim 1 or 2, wherein the PIL fills the entire void volume of the expanded porous membrane, or fills between 10% and 50% of the void volume of the expanded porous membrane, or fills between greater than 50% and 90% of the void volume of the expanded porous membrane.

4. 3. The composite material of claim 1 or 2, wherein the expanded porous membrane comprises one or more of polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), tetrafluoroethylene (TFE) copolymer, polylactic acid (PLA), polyparaxylylene (PPX), polyvinylidene difluoride (PVDF), vinylidene difluoride (VDF) copolymer, or poly(ethylenetetrafluoroethylene) (ETFE).

5. 3. The composite material of claim 1 or 2, wherein the expanded porous membrane comprises expanded polytetrafluoroethylene (ePTFE).

6. 3. The composite material of claim 1 or 2, wherein the composite material has a porosity of greater than 20% and up to 99%, or less than 20%.

7. 3. The composite material of claim 1 or 2, further comprising at least one active agent.

8. 8. The composite material of claim 7, wherein the active agent is covalently or non-covalently bound to the PIL, and the active agent is selected from the group consisting of inorganic particles, inorganic nanoparticles, metals, metal oxides, metal salts, carbon nanotubes (CNTs), fullerenes, graphene, catalyst particles, polyoxometalates (POMs), metal-organic frameworks (MOFs), additional polymers, silica, quantum dots, ionic liquids, biologically active molecules, and any combination thereof.

9. 3. The composite material of claim 1, wherein the weight percentage of the poly(ionic liquid) polymer relative to the total weight of the composite material ranges from 1 wt % to 90 wt %.

10. The composite material of claim 1 or 2, further comprising a support layer.

11. The composite material contains 0.3 mmol CO ２ / g PIL ∼ 1.2 mmol CO ２ / g PIL CO ２ Absorption capacity or CO greater than 1.0 barrer ２ or less than 1.5 barrer N ２ Permeability or CO ２ Transparency / N ２ 3. The composite material of claim 1 or 2, having a selectivity, calculated as permeability, greater than 8.

0.

12. A laminate comprising the composite material of claim 1 or 2.

13. An article comprising the composite material of claim 1 or 2.

14. 3. A method for separating a gas from a mixture, comprising providing a composite material according to claim 1 or 2, and separating the gas from the mixture by contacting the mixture with the composite material.

15. 15. The method of claim 14, wherein the gas is carbon dioxide.

16. (a)(i) a poly(ionic liquid) polymer solution (PIL), and (ii) providing an expanded porous membrane having a first side and a second side comprising expanded polytetrafluoroethylene (ePTFE) or expanded ultra-high molecular weight polyethylene (eUHMWPE), the expanded porous membrane having a microstructure consisting of fibrils, optionally nodes interconnecting the fibrils, and a void volume providing pores; and (b) depositing the poly(ionic liquid) polymer solution on at least one side of the expanded porous membrane to form a composite material; (c) optionally subjecting the composite material of step (b) to one or more steps of heating, stretching, compressing, or any combination thereof; 1. A method of forming a composite material, comprising: the PIL is selected from the group consisting of poly(diallyldimethylammonium)bis(trifluoromethane)sulfonimide (PDDMATFSI), poly(diallyldimethylammonium)chloride (PDDMACl), poly(diallyldimethylammonium)tetrafluoroborate (PDDMABF4), poly((vinylbenzyl)trimethylammonium)bis(trifluoromethane)sulfonimide (PVBTMATFSI), poly((vinylbenzyl)trimethylammonium)chloride (PVBTMACl), poly((vinylbenzyl)trimethylammonium)tetrafluoroborate (PVBTMABF4), and poly((vinylbenzyl)trimethylammonium)acetate (PVBTMAOAc).

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