Cross Reference To Related Applications

[0001] This application claims the benefit of priority U.S. provisional patent application No. 63/249,000, filed on September 27, 2021, U.S. provisional patent application No. 63/274,702 filed on November 2, 2021, U.S. provisional patent application No. 63/278,780 filed on November 12, 2021, and to U.S. provisional patent application No. 63/395,577, filed on August 5, 2022; the entirety all prior applications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

[0002] This invention is directed to an anion conductive polymer comprising a polypenylene backbone with functional groups on sidechains and anion exchange polymers and anion exchange membranes incorporating these polymere.

BACKGROUND OF THE INVENTION

[0003] Anion exchange membranes (AEMs) are solid polymer electrolyte membranes which allow for the transportation of anions (e.g. OH-, CͰ, Br) under a chemical or electrical potential. Anion exchange membranes consist of polymere containing fixed positively charged functional groups and mobile negatively charged Ions.

[0004] Anion exchange membranes are a critical component of hydroxide exchange membrane fuel cells (HEMFC), where hydrogen and oxygen are used to generate electricity with water as a byproduct. Anion exchange membranes are also used in alkaline membrane water electrolysis, where water is split into hydrogen and oxygen using electricity. In both anion exchange membrane fuel cells and water electrolysis, hydroxide ions and water are transported across the membrane. HEMFCs and alkaline membrane electrolyzers have garnered recent Interest due to their potential to eliminate the need for expensive platinumgroup catalysts, fluorinated ionomers, and acid-resistant metals in these electrochemical systems. AEMs may also be used In batteries, sensors, electrochemical compressors, and various separation applications.

[0005 Anion exchange membranes require a higher activation energy for hydroxide ion transport compared to proton transport In proton exchange membranes. To achieve high ionic conductivity and hydrophilic-domain phase separation, anion exchange membranes are designed to have high ion exchange capacity. High Ion exchange capacity increases water uptake and hydrophilic-domain phase separation, leading to a reduction in mechanical strength and dimensional stability. Traditionally, to combat these issues, thicker membranes are used. However, thicker membranes have higher ionic resistance, lowering the performance in a device.

[0006] Anion exchange membranes (AEMs) are solid polymer electrolyte membranes which allow for the transportation of anions (e.g. OH", Cl", Br) under a chemical or electrical potential. AEMs consist of polymers containing fixed positively charged functional groups and mobile negatively charged ions.

[0007] In recent years, proton exchange membrane fuel cells including solid polymer membrane as the electrolyte has been widely studied due to their high efficiency and density as well as low start temperature. However, the use of noble metal catalysts such as platinum has been an obstacle of viable commercialization of proton exchange membrane fuel cells. Also, high pH condition is a significant requirement for alkaline membrane fuel cells, which limits the utilization of proton exchange membrane. Therefore, the interest of developing anion exchange membranes (AEM) for alkaline fuel cells has prominently grown due to the low overpotentials caused by electrochemical reactions at alkaline environment and the dispensation of noble metal catalysts. A good anion exchange membrane for alkaline fuel cells should be with necessary conductivity, chemical and mechanical stability. Moreover, low cost is another significant requirement of developing new anion exchange membranes. For example, a well-known cation exchange membrane (Nation) developed by DuPont contributes up to 40% of the total cost of some redox flow batteries. Hence, the high cost rendered people to seek more cheaper alternatives, primarily anion exchange membranes. Up to now, most commercially available anion exchange membranes are based on cross- linked polystyrene, which are not chemically stable in alkaline environments. Some other aryl ether-containing polymer backbones of anion exchange membranes tend to be attacked by hydroxide ions, which causes the degradation of the polymers.

[0008] There is therefore a need for inexpensive, chemically stable AEM materials with controlled water uptake to enable the performance of developing electrochemical and separation systems.

SUMMARY OF THE INVENTION

[0009] The present invention provides an anion conducting co-polymer and a composite anion conducting membrane that may include a porous scaffold support. The anion conducting co-polymer includes a poly(phenylene) backbone and an aromatic compound bond to the poly(phenylene) backbone by a linking compound. The poly(phenylene) backbone has sidechains that are terminated with functional terminal groups configured on sidechains of the poly(phenylene) backbone. The functional groups may be quaternary ammonium or n-methyl piperidine functional groups. A porous scaffold support, such as a porous membrane may be incorporated into a composite anion conducting membrane for reinforcement. Typically, the anion exchange membrane is prepared by imbibing the porous scaffold support with an anion exchange polymer solution of a non-ionic precursor polymer followed by conversion of a functional moiety on the polymer to form quaternary ammonium or n-methyl piperidine cation. Such a conversion can be accomplished by treatment of the precursor anion exchange membrane with basic trimethylamine or aqueous solution or N- Methylpiperidine DMSO solution. The thickness of an anion conducing membrane may be preferably very thin, such about 50 micrometers or less, about 25 micrometers or less, about 10 micrometers or less, and in some embodiments about 5 micrometers or less.

[0010] Exemplary poly(phenylene) may have functional groups selected from the group of quaternary ammoniums, n-methyl piperidine, tertiary diamines, phosphonium, benz(imidazolium), sulphonium, guanidinium, metal cations, pyridinium. Preferably the functional group is quaternary ammonium or n-methyl piperidine.

[0011] An exemplary porous scaffold support is made from polymer group consisting of polyolefins, polyamides, polycarbonates, cellulosics, polyacrylates, copolyether esters, polyamides, polyarylether ketones, polysulfones, polybenzimidazoles, fluoropolymers, and chlorinated polymers.

[0012] Exemplary polyphenylene may have additive selected from a group consisting of radical scavengers, plasticizers, fillers, anion conducting material, crosslinking agent.

[0013] The present invention provides a mechanically reinforced anion exchange membrane comprising a functional polymer based on a poly(phenylene) backbone with quaternary ammonium functional groups and an inert porous scaffold support for reinforcement. Typically, the anion exchange membrane is prepared by imbibing the porous scaffold support with a polymer solution of a non-ionic precursor polymer followed by conversion of a functional moiety on the polymer to form a trimethyl ammonium cation. Such a conversion can be accomplished by treatment of the precursor polymer membrane with trimethylamine. In addition, an optional chemical crosslinking reaction can also be used to toughen the polymer by converting it from a thermoplastic to a thermoset material. Such a conversion can be accomplished by treatment of the precursor polymer membrane by a diamine, which is typically performed before the amination reaction. Typically, the thickness of the functionalized membrane is 25 micrometers or less, more typically 10 micrometers or less, and in some embodiments 5 micrometers or less.

[0014] The polyphenylene co-polymers integrated with functionalized fluorene are presented in this embodiment. Carbon-carbon coupling polymerizations such as has been successfully used to synthesize poly(phenylene)s, is costly and strict to the environment of storing palladium-containing catalysts. In the present invention a super-acid catalyzed Friedel-Crafts polycondensation for the synthesis of the co-polymer mixtures is used comprising:

A trifluoroacetone monomer having the chemical structure (1): an aromatic monomer having the structure (3):

Or

(3) a 9,9-Bis(bromoalkane)-9H-fiuorene monomer having the structure (4)

(4)

Wherein:

Ri is phenyl. n is in the range of 1-6

The anion exchange co-polymers having the formula (1):

(D

Wherein:

Ar is selected from the anyone from Formula (3) R2 is selected from

[0015] The hydroxide exchange co-polymers are synthesized which comprises ether free functionalized polyphenylene backbones integrated with functionalized fluorene. The water uptake, IEC and conductivity.

[0016] A method of synthesizing the hydroxide exchange co-polymers shown in Formula (1) is described below, which comprises that reacting monomers shown in Formula (1) in organic solvent with super acid catalyst to form neutral intermediate polymers; quatemization of the neutral intermediate polymer in organic solvent to form ionic polymer; dissolvent the ionic polymer in organic solvent for solution-casting membranes; the membrane is immersed in base solution for ion exchange to form hydroxide exchange membrane.

[0017] The polyphenylene backbone is a polycyclic aromatic with a center with five carbons and two benzene rings on either side of said center ring. The polyphenylene backbone has a pair of sidechains that each extend to a respective terminal group, such as bromine, which can be functionalized with a functional group (Fn), such as quaternary ammonium or n-methyl piperidine.

[0018] The sidechains may be hydrocarbon and may have four or more carbons, six or more carbons, eight or more carbons and any range between and including the number carbons listed. A longer sidechain may provide high anion conductivity as the functional groups responsible for anion conduction may be more mobile. The linking compound may include sidechains and one of the sidechains may include a fluorinated group, such as a C-F group including a C-F2 group or a CF-3 group. The linking compound may include an aromatic ring, such as benzene, as a terminal group on a sidechain.

[0019] The ratio of the polyphenylene backbone to the aromatic compound may be specifically designed to provide good mechanical strength of the anion conducing copolymer while providing effectively high anion conductivity. A higher concentration of aromatic compound will make the anion conducing co-polymer softer and less crystalline and also more hydrophobic. Therefore, it is desirable to keep the concentration of the compound effective low, as described herein. A higher concentration of the polyphenylene backbone will make the anion conducting co-polymer tougher. The ratio of the poly(phenylene) backbone concentration (number of polycyclic aromatic compounds) to the aromatic compound concentration (number of aromatic compounds) is at least 40:1, at least 100: 1 , least 200: 1. Put another way, the anion conducting co-polymer may have a concentration of the aromatic structure that is no more than 5%, or even no more than 2%, of a combined molecular weight of the poly(phenylene) backbone and the aromatic structure

[0020] The porous scaffold may be a microporous scaffold having an average or mean flow pore size of less than 1 micron as determined by a Capillary Flow Porometer, available from Porous Materials, Inc. Ithaca, NY, and the mean flow pore size may be about 0.5 microns or less, or even about 0.25microns or less. A porous scaffold may be a porous fluoropolymer, such as expanded polytetrafluoroethylene or a porous olefin, such as a porous polyethylene and the like.

[0021] The summary of the invention is provided as a general introduction to some of the embodiments of the invention, and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0023] Figure 1 shows cross-sectional view of an exemplary porous scaffold support having a porous structure and pores therein, wherein the anion exchange polymer substantially fills the pores of the scaffold support.

[0024] Figure 2 shows a cross-sectional view of an exemplary ultra-thin composite anion exchange polymer film having a layer of anion exchange polymer on either side of the porous scaffold support.

[0025] Figure 3 shows cross-sectional view of an exemplary ultra-thin composite anion exchange polymer film formed by imbibing anion exchange polymer copolymer into a porous scaffold support using solution casting process, wherein the anion exchange polymer substantially fills the pores of the scaffold support.

[0026] Figure 4 shows a cross-sectional view of a composite anion exchange polymer film having a butter-coat layer of anion exchange polymer on the surface of a porous scaffold support.

[0027] Figure 5 shows a cross-sectional view of a composite anion exchange polymer tube with two layers of composite anion exchange polymer film. The overlap of two composites is achieved by wrapping the composite film around itself spirally.

[0028] Figure 6 shows a perspective view of an exemplary anion exchange polymer tube that comprises of a spirally wrapped composite anion exchange polymer film.

[0029] Figure 7 shows a perspective view of an exemplary anion exchange polymer tube that comprises of longitudinally wrapped anion exchange polymer tube in a spiral fashion resulting in overlap areas.

[0030] Figure 8 shows pervaporation module compromising a plurality of composite anion exchange polymer pervaporation tubes.

[0031] Figure 9 shows a cross sectional view of an exemplary composite anion exchange polymer tube having an anion exchange polymer layer on the outside surface of the porous scaffold support and a film layer configured over the anion exchange polymer layer. [0032] Figure 10 shows a cross sectional view of an exemplary composite anion exchange polymer tube having an anion exchange polymer layer on the inside surface of the porous scaffold support and a film layer configured over the anion exchange polymer layer.

[0033] Figure 11 shows a cross sectional view of an exemplary composite anion exchange polymer tube having an anion exchange polymer layer on both the inside and the outside surface of the porous scaffold support and a film layer over both anion exchange polymer layers.

[0034] FIG. 12 shows a polymer diagram for polyphenylene wherein Ar is the polyphenylene backbones, R1 is phenyl and X is halide terminal which can be functionalized.

[0035] Figure 13 shows the components of the anion conducting co-polymer including the poly(phenylene) backbone, the aromatic structure and the linking compound configured therebetween.

[0036] Figure 14 is the symbatic pathways to produce the anion conducting co-polymer for formula 1.

[0037] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0038] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0039] As used herein, the terms “comprises,” “comprising," “includes,” “including,” “has," “having" or any other variation thereof, are intended to cover a non-exdusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a" or “an" are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0040] Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0041] An anion exchange polymer is used synonymous with anion conducting polymer or anion conducting co-polymer, herein.

[0042] As shown in FIG. 1, an exemplary porous scaffold support 10 is a thin sheet or porous membrane having a top side 12, bottom side 14 and pores 16 therethrough from the top to the bottom. An exemplary porous scaffold support is a planar sheet of material having a thickness 13 of less than 50 pm, and preferably less than 25 pm.

[0043] As shown in FIG. 2, an exemplary composite anion exchange polymer film 40 has anion conducting co-polymer or anion exchange polymer 30 imbibed into the pores 16 of the porous scaffold support 10. This may be accomplished by melt laminating and pressing anion exchange polymer resin into the pores of the porous scaffold material, or through solution casting or imbibing. The composite anion exchange polymer film has a top surface 42 and a bottom surface 44 and a thickness 43 therebetween. The thickness of the composite anion exchange polymer film is preferably less than 50 pm, more preferably less than 25 pm and even more preferably less than 10 pm or 5 pm. There is an anion conducting co-polymer butter coat layer 48, 48' extending across the top side 12 and bottom side 14 of the porous scaffold support, respectively. A butter coat layer is a thin layer of the anion exchange polymer extending over the porous scaffold support. A butter-coat layer may be on one or both surfaces of the composite anion exchange polymer film.

[0044] As shown in FIG. 3, an exemplary ultra-thin composite anion exchange polymer film 40 has anion exchange polymer 30 imbibed into the pores 16 of the porous scaffold support 10. This may be accomplished by melt laminating and pressing anion exchange polymer resin into the pores of the porous scaffold material, or through solution casting or imbibing. In this embodiment, there is no butter-coat layer. [0045] As shown in FIG. 4, a composite anion exchange polymer film 40 has a buttercoat layer 48 of anion exchange polymer 30 which may be a copolymer on the top side 12 or surface of a porous scaffold support 10. This thin composite anion exchange polymer film may be used in a flat sheet in a pervaporation module or in a humidification vent application to allow humidity to pass therethrough but to exclude other contaminants or particles from entering an enclosure. As shown in FIG. 4, a flat sheet of a composite anion exchange polymer film may be made for plate and frame configurations. It may be preferable to use this single sided butter-coat layer composite anion exchange polymer film for these applications as the anion exchange polymer may be very thin, such as less than 10 pm or even more preferably less than 5 pm.

[0046] Figure 5 shows a cross-sectional view of an overlap area 58 of a composite anion exchange polymer tube having two layers of composite anion exchange polymer film 40 and 40’. The overlap area is fused together along the fused interface 20 which may include anion exchange polymer from one butter-coat layer melting into the anion exchange polymer of the adjacent butter-coat layer. Note that anion exchange polymer from one composite anion exchange polymer film may melt into the pores or other anion exchange polymer in an adjacent composite anion exchange polymer film. The thickness 23 of the overlap area 58 or layers is greater than the thickness of a single composite anion exchange polymer film, and therefore reducing the overlap area is important to increase throughput and permeation rates through the tube.

[0047] As shown in FIG. 6, a composite anion exchange polymer tube 50 is a spirally wrapped anion exchange polymer tube 60 having a composite anion exchange polymer film 40 spirally wrapped to form the outer wall 52 and conduit 51 of the spirally wrapped anion exchange polymer tube. The spirally wrapped anion exchange polymer tube has overlap areas 58 that spiral around the tube. The composite anion exchange polymer film that may be attached or bonded to each other to form bonded area 59. The bonding may be formed by fusing the layers together, wherein the anion exchange polymer from one layer is intermingled with the anion exchange polymer of the second, or overlapped layer. This bonding may be accomplished through heat, such as by fusing or by the addition of a solvent that enables intermingling of the polymers. The composite anion exchange polymer tube 50 has a length 55 from an inlet 54 to an outlet 56 and a length axis 57 extending along the center of the tube. A first layer of the composite anion exchange polymer film is bonded to the anion exchange polymer of a second layer of the composite anion exchange polymer film to form the bonded area. As described herein, the overlap width may be fraction of the tape width, such as no more than about 30% of the tape width, no more than about 25% of the tape width, no more than about 20% of the tape width, no more than about 10% of the tape width, or even no more than about 5% of the tape width to provide a high percentage of the spiral wrapped tube that is only a single layer, thereby increase the rate of transfer of ions through the tube and also reduce the total usage of film thus lower cost.

[0048] As shown in FIG. 7, a composite anion exchange polymer tube 50 is a longitudinally wrapped anion exchange polymer tube 70 having a composite anion exchange polymer film 40 longitudinally wrapped to form the longitudinally wrapped anion exchange polymer tube and tube conduit 51. The longitudinally wrapped anion exchange polymer tube has an overlap area 58 of the composite anion exchange polymer film that extends down along the length 55 or length axis 57 of the tube. The length extends from the inlet 54 to the outlet 56. The overlap area may be attached or bonded to each other to form a fused area 59 wherein the layers of the composite anion exchange polymer film are bonded or fused together, wherein the anion exchange polymer from one layer is intermingled with the anion exchange polymer of a second layer through melting or solvent bonding. The bonding may be formed by fusing the layers together, wherein the anion exchange polymer from one layer is intermingled with the anion exchange polymer of the second, or overlapped layer. This bonding may be accomplished through heat, such as by fusing or by the addition of a solvent that enables intermingling of the polymers. An exemplary composite anion exchange polymer pervaporation tube comprises a longitudinally wrapped, or “cigarette wrapped” composite anion exchange polymer film sheet to form a longitudinal wrapped anion exchange polymer pervaporation tube. The composite anion exchange polymer film is wrapped around the longitudinal axis of the tube. In this embodiment the length of the tube is the width of the composite anion exchange polymer film, and the wrap angle is perpendicular to the longitudinal axis. The longitudinal wrapped composite anion exchange polymer film has an overlap area having an overlap width. Again, the overlap width may be no more than about 30% of the tape width, no more than about 25% of the tape width, no more than about 20% of the tape width, no more than about 10% of the tape width, or even no more than about 5% of the tape width to provide a high percentage of the spiral wrapped tube that is only a single layer, thereby increase the rate of permeation and transfer of ions through the tube.

[0049] FIG. 8 shows a pervaporation module 80 comprises a plurality of anion exchange polymer pervaporation tubes 82 that are composite anion exchange polymer pervaporation tubes 84, as described herein 32. Each of the tubes is coupled to an inlet tube sheet 85 and outlet tube sheet 89. A flow of water flows through the plurality of tubes from the inlet 54 to the outlet 56 of the tube. An airflow 87 passes over the tubes to pull away moisture. The inlet relative humidity 86 may be much lower than the outlet relative humidity 88. Each of the composite anion exchange polymer tubes may further comprise a tube support 90, which is an additional support structure or tube that extends around the composite anion exchange polymer tubes to prevent expansion of the composite anion exchange polymer tubes under pressure. The water flowing through the tubes may be pressurized to increase permeation therethrough and a tube support may prevent diameter creep or swelling. A tube support may be a net or screen that is resistant to radial forces that would increase the diameter and may be made of rigid polymer material and/or a metal, such as a porous metal tube including, but not limited to a, perforated metal tube or woven metal tube.

[0050] As shown in FIG. 9, an exemplary composite anion exchange polymer tube 50 has an anion exchange polymer layer 32 on the outside surface 64 of the composite tube comprising a porous scaffold support 10. The composite anion exchange polymer tube has a film layer 100 configured over the wrapped composite anion exchange polymer film 40 to provide additional support and prevent leakage. An exemplary film layer may be thin, having a thickness no more than about 15 pm more than about 10 pm, no more than about 5 pm, no more than about 2 pm, no more than about 1 pm and any range between and including the thickness values provided. When the film layer is or comprises anion exchange polymer, the thinner the better for moisture transfer rates.

[0051] As shown in FIG. 10 an exemplary composite anion exchange polymer tube 50 has an anion exchange polymer layer 32 on the inside surface 62 of the composite tube comprising a porous scaffold support 10. The composite anion exchange polymer tube has a film layer 100 configured over the wrapped composite anion exchange polymer film 40 to provide additional support and prevent leakage.

[0052] As shown in FIG. 11, an exemplary composite anion exchange polymer tube 50 has an anion exchange polymer layer 32 on both the inside surface 62 and the outside surface 64 of the composite tube comprising a porous scaffold support 10. The composite anion exchange polymer tube has a film layer 100, 100’ configured over the wrapped composite anion exchange polymer film 40 on the outside surface and inside surface, respectively, to provide additional support and prevent leakage. The tube may be an extruded tube.

[0053] Example 1:

[0054] The anion conducting co-polymers were prepared by super-acid catalytic polymerization. In one embodiment, a membrane was prepared by dissolving the precursor polymer in tetrahydrofuran at a 10% weight ratio i.e. 1 grams of the ionomer to 10.0 g of solvent. The mixture was stirred until homogenous and translucent. The precursor ionomer solution was then applied to a microporous polyethylene material tensioned around a chemically resistant plastic frame. The ionomer solution was then poured on to the microporous scaffold. The frame was covered with a lid to slow solvent evaporation. The membrane was dried at room temperature for 24 hours. The final thickness of the precursor membrane was 5 micrometers. The precursor ionomer was then applied to a microporous polytetrafluoroethylene) material with a doctor blade. The precursor ionomer membrane was covered with a lid to slow solvent evaporation. The membrane was dried at room temperature. The final thickness of the membrane was 15 microns. It will be apparent to those skilled in the art that the latter embodiment can be scaled up to a roll-to-roll, continuous process. In the case of either embodiment, multiple coatings can be applied to increase the membrane thickness or to facilitate filling of the porous material. In the case of either embodiment, the precursor ionomer membrane is not needed to be further aminated.

[0055] Polymers may be compatible with porous scaffold for imbibing the polymers into the pores of the porous scaffold. The polymers consisted of an all-hydrocarbon polymer backbone which was chemically stable polymer even under harsh working conditions, such as 80°C in 1 M NaOH. Efficient ion channels were engineered into the AEM by synthesis of a block copolymer. The block copolymer was composed of at least two blocks: hydrophilic ones which were functionalized with tethered cation groups for anion conduction, and hydrophobic ones to facilitate phase segregation of the polymer so as to form efficient anion conductive channels.

[0056] In addition to forming efficient ion conducting channels within the AEM material by itself, the AEM/scaffold composite has lower water uptake and is structurally more robust than the neat AEM polymer. Control over excess water uptake is a critical parameter is AEM applications. In addition, the poly(phenylene) polymer used here is compatible and sufficiently adherent to the scaffold to form a reliable integrated structure. The high intrinsic mechanical compliance and toughness of the poly(phenylene) AEM allows the use of very thin scaffolds resulting in composites which have very low area specific resistance and water uptake

[0057] Example 2:

[0058] In one embodiment, a membrane was prepared by dissolving the precursor polymer in toluene at a 10% weight ratio i.e. 0.25 grams of polymer to 2.50 g of solvent. The mixture was stirred until homogenous and translucent. The precursor polymer solution was then applied to a microporous polyethylene material tensioned around a chemically resistant plastic frame. The polymer solution was then poured on to the microporous scaffold. The frame was covered with a lid to slow solvent evaporation. The membrane was dried at room temperature. The final thickness of the precursor membrane was 5 micrometers.

[0059] In another embodiment, a membrane is prepared by dissolving the precursor polymer in toluene at a 5% weight ratio i.e. 0.3 grams of polymer to 5.7 g of solvent. The mixture was stirred until homogenous and translucent. The precursor polymer was then applied to a microporous poly(tetrafluoroethylene) material with a doctor blade. The precursor polymer membrane was covered with a lid to slow solvent evaporation. The membrane was dried at room temperature. The final thickness of the membrane was 15 microns. In the case of either embodiment, multiple coatings can be applied to increase the membrane thickness or to facilitate filling of the porous material. In the case of either embodiment, the precursor polymer membrane can be soaked in trimethylamine solution in water or ethanol to convert the haloalkyl moieties within the precursor polymer to a trialkyl ammonium head-group enabling anion conduction within the membrane. The mobile halogen counter ion (e.g. bromide, chloride or iodide) can later be exchanged with hydroxide ions.

[0060] Optionally, the precursor polymer membrane can contain or be soaked in a diamine, such as tetramethyl hexyldiamine, to cross-link some or all of the haloalkyl moieties. The cross-linking is preferably carried out before the amination reaction in trimethylamine; however, cross-linking may also be carried out after amination.

[0061] Polymers compatible with porous scaffold embedded into it. The polymers consisted of an all-hydrocarbon polymer backbone which was chemically stable polymer even under harsh working conditions, such as 80°C in 1 M NaOH. Efficient ion channels were engineered into the AEM by synthesis of a block copolymer. The block copolymer was composed of at least two blocks: hydrophilic ones which were functionalized with tethered cation groups for anion conduction, and hydrophobic ones to facilitate phase segregation of the polymer so as to form efficient anion conductive channels

[0062] In addition to forming efficient ion conducting channels within the AEM material by itself, the AEM/scaffold composite has lower water uptake and is structurally more robust than the neat AEM polymer. Control over excess water uptake is a critical parameter is AEM applications. In addition, the poly(phenyiene) polymer used here is compatible and sufficiently adherent to the scaffold to form a reliable integrated structure. The high intrinsic mechanical compliance and toughness of the poly(phenylene) AEM allows the use of very thin scaffolds resulting in composites which have very low area specific resistance and water uptake.

[0063] Referring now to FIGS. 12 to 14, an anion conducing co-polymer 500 includes a polyphenylene backbone 502 and an aromatic compound 508, wherein the polyphenylene backbone 502 has sidechains 504, 504’ that extend to a respective terminal group 505, 505' that can be reacted to produce a functional group 503. FIG. 12 shows a polymer diagram of an anion conducting co-polymer 500 having a polyphenylene backbone 502 and an aromatic compound 508, (Ar), with a linking compound 506 configured between the aromatic compound and the polyphenylene backbone. The polyphenylene backbone is a polycyclic aromatic with a center with five carbons and two benzene rings on either side of said center ring. The polyphenylene backbone has a pair of sidechains 504, 504' that each extend to a respective terminal group 505, 505', such as bromine, which can be functionalized with a functional group (Fn), such as quaternary ammonium or n-methyl piperidine. [0064] The sidechains may be hydrocarbon and may have four or more carbons, six or more carbons, eight or more carbons and any range between and including the number carbons listed. A longer sidechain may provide high anion conductivity as the functional groups responsible for anion conduction may be more mobile. The linking compound may include sidechains and one of the sidechains may include a fluorinated group, such as a C-F group including a C-F2 group or a CF-3 group. The linking compound may include an aromatic ring, such as benzene, as a terminal group on a sidechain.

[0063] The ratio of the polyphenylene backbone to the aromatic compound may be specifically designed to provide good mechanical strength of the anion conducing copolymer while providing effectively high anion conductivity. A higher concentration of aromatic compound will make the anion conducing co-polymer softer and less crystalline and also more hydrophobic. Therefore, it is desirable to keep the concentration of the compound effective low, as described herein. A higher concentration of the polyphenylene backbone will make the anion conducting co-polymer tougher. The ratio of the poly(phenylene) backbone concentration (number of polycyclic aromatic compounds) to the aromatic compound concentration (number of aromatic compounds) is at least 40:1 , at least 100:1, least 200:1. Put another way, the anion conducting co-polymer may have a concentration of the aromatic structure that is no more than 5%, or even no more than 2%, of a combined molecular weight of the poly(phenylene) backbone and the aromatic structure.

[0064] As shown in FIG. 13, the anion conducting co-polymer includes three components, a polyphenylene backbone 502 and an aromatic compound 508 chemically bonded to the polyphenylene backbone by a linking compound 506. The aromatic compound may be any suitable aromatic compound such as p-terphenyl, m-terphenyl, biphenyl, and 1,3,5-Triphenylbenzene as shown.

[0065] The anion conducting co-polymer may be converted with a functional moiety on the polymer to form a trimethyl ammonium cation. Such a conversion can be accomplished by treatment of the precursor polymer membrane with trimethylamine. An optional chemical crosslinking reaction can also be used to toughen the polymer by converting it from a thermoplastic to a thermoset material. Such a conversion can be accomplished by treatment of the precursor polymer membrane by a diamine, which is typically performed before the amination reaction. An additives like radical scavengers, plasticizers, fillers, anion conducting material can also be added to improve membrane properties.

[0066] Referring to FIG. 14, according to one embodiment, a synthetic route and a composition are disclosed. The polymer is produced by reaction of compounds shown in FIG. 13, including poly(phenylene) that forms the backbone of the polymer a linking compound 506 and an aromatic compound 505. [0067] Details of a process for synthesizing the target ionomer shown in the FIG. 14 and are further described in Example 1.

Example 3: Synthesis of the anion conductive polymer shown in FIG. 16.

[0068] For the synthesis, a 100 ml three-neck flask was added with a mixture of 9,9- Bis(6-bromohexyl)-9H-fluorene (2.4 g, 4.88 mmol, 1.0 eq), biphenyl or m-terphenyl or p- terphenyl or 1,3,5-Triphenylbenzene (0.5%-1.5% eq), 2,2,2-trifluoroacetophenone (1.2 eq), 8 ml trifluoromethanesulfonic acid in 8 ml dichloromethane under argon. The mixture was running at room temperature for 24 h until the mixture is viscous. Then, the mixture solution was poured into cold methanol and white precipitation was obtained through vacuum filtration. After washing the solids with hot methanol and water, the aqueous solution containing trimethylamine was added with the solids and stirred at room temperature for overnight. The target polymer was obtained after vacuum filtration and washing with water.

[0069] It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.