Porous air permeable expanded PTFE composite with enhanced mechanical and thermal properties are described. The node and fibril microstructure of expanded PTFE is coated on and within the node and fibril microstructure with a suitably chosen polymer to impart property enhancement while maintaining porosity. The coating polymer content of the composite is maintained between 3 and 25 weight percent of the composite and the areal mass of the composite is less than 75 gm/m.sup.2. Exemplary enhancement to properties may include, among others, Average Tensile Strength (ATS) (in MPa)?Z strength (in MPa) of 50 MPa.sup.2 or greater, preferably 100 MPa.sup.2 or greater, with air flow less than 500 Gurley seconds. Coating polymers with appropriate temperature resistance provides composites which further exhibit shrinkage of less than 10% at temperatures up to 300? C. with air flow of less than 500 Gurley seconds.

Disclosed is an ion-exchange membrane that includes a molecular barrier for influencing permeation selectivity through the membrane. The membrane includes fluorinated carbon backbone chains and fluorinated side chains that extend off of the fluorinated carbon backbone chains. The fluorinated side chains include acid groups for ionic conductivity. The acid groups surround and define permeable domains that are free of the fluorinated carbon backbone chains. Molecular barriers are located in the permeable domains and influence permeability through the domains.

A polymer electrolyte membrane fuel cell that includes a positive electrode, a negative electrode, a polyelectrolyte membrane and a solution of reduced graphene oxide and/or graphene oxide functionalized with metallized nanoparticles. The electrodes are coated with a polymer and the polyelectrolyte membrane has a hydrophobic exterior surface that is subjected to ultraviolet/ozone (UV/O.sub.3) exposure, which changes the hydrophobic, exterior surface to a hydrophilic exterior surface. The polyelectrolyte membrane is disposed between the positive electrode and the negative electrode and can include a sulfonated tetrafluoroethylene based fluoropolymer-copolymer. The solution forms a coating on the hydrophilic exterior surface of the polymer electrolyte membrane and the positive and negative electrodes. The positive and negative electrodes can be coated with a polymer, preferably polytetrafluoroethylene (PTFE) that can be subjected to ultraviolet/ozone (UV/O.sub.3) exposure. The metallized nanoparticles increase the efficiency of the fuel cell by at least 50% when the feed gas includes at least 1000 ppm carbon monoxide.

Porous air permeable expanded PTFE composite with enhanced mechanical and thermal properties are described. The node and fibril microstructure of expanded PTFE is coated on and within the node and fibril microstructure with a suitably chosen polymer to impart property enhancement while maintaining porosity. The coating polymer content of the composite is maintained between 3 and 25 weight percent of the composite and the areal mass of the composite is less than 75 gm/m.sup.2. Exemplary enhancement to properties may include, among others, Average Tensile Strength (ATS) (in MPa)Z strength (in MPa) of 50 MPa.sup.2 or greater, preferably 100 MPa.sup.2 or greater, with air flow less than 500 Gurley seconds. Coating polymers with appropriate temperature resistance provides composites which further exhibit shrinkage of less than 10% at temperatures up to 300 C. with air flow of less than 500 Gurley seconds.

Disclosed are a copolymer, porous membranes made from the copolymer, and a method of treating fluids using the porous membranes to remove metal ions, for example, from fluids originating in the microelectronics industry, wherein the copolymer includes polymerized monomeric units I and II, wherein monomeric unit I is of the formula A-XCH.sub.2B, wherein A is Rf(CH.sub.2)n, Rf is a perfluoro alkyl group of the formula CF.sub.3(CF.sub.2).sub.x, wherein x is 3-12, n is 1-6, X is O or S, and B is vinylphenyl, the monomeric unit II is haloalkyl styrene, and optionally wherein the halo group of haloalkyl is replaced with an optional substituent, for example, ethylenediamine tetra acetic acid, iminodiacetic acid, or iminodisuccinic acid.

Porous air permeable expanded PTFE composite with enhanced mechanical and thermal properties are described. The node and fibril microstructure of expanded PTFE is coated on and within the node and fibril microstructure with a suitably chosen polymer to impart property enhancement while maintaining porosity. The coating polymer content of the composite is maintained between 3 and 25 weight percent of the composite and the areal mass of the composite is less than 75 gm/m.sup.2. Exemplary enhancement to properties may include, among others, Average Tensile Strength (ATS) (in MPa)?Z strength (in MPa) of 50 MPa.sup.2 or greater, preferably 100 MPa.sup.2 or greater, with air flow less than 500 Gurley seconds. Coating polymers with appropriate temperature resistance provides composites which further exhibit shrinkage of less than 10% at temperatures up to 300? C. with air flow of less than 500 Gurley seconds.

An anion exchange ionomer is disclosed that contains a fluorinated, ether-free backbone, and a fluorinated ether based quaternary ammonium functional group. The novel polymer has improved chemical and mechanical stability as compared to the state-of-the-art materials for incorporation in anion exchange membrane. The disclosed anion exchange ionomer may be incorporated into an anion exchange membrane and used in electrochemical applications.

The present invention provides composite particles which are capable of forming an ion exchange membrane with fewer defects and an ion exchange membrane. The composite particles according to the present invention comprise pellets comprising a fluorinated polymer having groups convertible to ion exchange groups, and a powder held on the pellet surface which comprises a polymer, wherein the powder has an average particle diameter of at least 1 m and at most 1,000 m, and the ratio of the average particle diameter of the pellets to the average particle diameter of the powder is 2 to 4,500.

A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

Provided herein are membrane electrode assemblies (MEAs) for CO.sub.x reduction and carbon dioxide reduction reactors (CRRs) that include MEAs.