TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The ion exchange material is an ionomer comprising perfluorosulfonic acid ionomers, aromatic polymers having fluoroalkylsulfonate groups, partially fluorinated sulfonated ionomers, perfluoroalkyl-based ionomers, sulfonated aromatic polymers, polyimidazole with phosphoric acid, sulfonated polyethersulfone, sulfonated poly(ether etherketones), sulfonated polypropylene oxide, sulfonated polyimides, sulfonated polyetherimides, sulfonated polyesters, chlorosulfonated polyethylene or sulfonated poly(phenylene sulfide). The perfluoroalkyl-based ionomers comprise PTFE sulfonic acid or polyperfluorosulfonic acid ionomer. The partially fluorinated sulfonated ionomers comprise sulfonated styrene polyvinylidene difluoride-based copolymers, poly( alpha , beta , beta -trifluoromethylstyrene sulfonic acid) or aromatic polymers having organic fluorosulfonic acid groups or their derivatives. The porous base membrane comprises PTFE, polyolefin, polyamide, polyester, polysulfone, polyether, acrylic and methacrylic polymers, polystyrene, polyurethane, polypropylene, polyethylene, polyphenylene sulfone, and/or cellulosic polymer. It also comprises expanded PTFE. The primer comprises fluorinated vinyl-based copolymer having sulfonyl functionality, hydrocarbon-based polymer containing random sulfonation, a hydrocarbon-based polymer containing blocky, mixed or gradient sulfonation, a partially fluorinated block copolymer containing sulfonated hydrophilic segment, hydrophobic fluorinated segment, vinylic-based, acrylic-based or styrenic-based polymers and copolymers or poly(vinyl acetate)-based polymers. It comprises vinylidene difluoride copolymer. The primer is a vinylidene difluoride and sulfonated perfluoroalkyl vinyl ether copolymer of formula (I). The primer comprises perfluorosulfonic acid, sodium sulfonated-perfluorosulfonic acid, sulfonyl fluoride-perfluorosulfonic acid or sodium perfluorosulfonate polymer. The weight ratio of the ion exchange material to the base membrane is 1:10 to 10:1.k=0-0.99. EXAMPLE - An expanded PTFE (ePTFE) membrane with dimensions of 12 inches by 12 inches and a thickness of 0.003 inches was uniformly coated with a modified vinylidene difluoride (VF2)-primer by supercritical carbon dioxide deposition in a vessel. The coating was then radically crosslinked by subjecting the membrane to a solution comprising (vol.%) triallylisocyanurate (1), toluene diisocyanate (0.4) and Trigonox 101 (RTM: 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane) (0.1), in supercritical carbon dioxide at 40 degrees C and 1900 psi. The peroxide made up approximately 3 mol% of the crosslinking composition. The pressure was slowly lowered to 250 psi in the vessel and the vessel was heated to 200 degrees C. After 10 minutes, the vessel was cooled and vented and the membrane was removed. The primer was converted to the sodium sulfonated salt via post-treatment with trimethyl silonate sodium salt. The membrane was placed into a shallow treatment pan and 0.15 M trimethyl silonate sodium salt (20 ml) in chloroform was syringed onto the membrane. After 10 minutes, the membrane was transferred to another shallow treatment pan and rinsed with chloroform (150 ml). After treatment, the membrane was estimated to have a VF2:primer content of 20 wt.% and an estimated sulfonate content of 700 equivalent weight. The VF2:ePTFE was completely wetted out in an ion exchange material, Nafion 117 (RTM: 5% perfluorosulfonic acid (PFSA)) solution in solvent (20% solution of the PFSA in isopropanol/water mix) using a vacuum microfiltration assembly. The ePTFE was mounted and the PFSA solution was deposited by vacuum suction (27 inches-mercury). The ePTFE was flipped onto its backside and the vacuum deposition was repeated. The base membrane was impregnated with the PFSA in a ratio of 2:1. The wet ePTFE was dried at 130 degrees C for 1 minute, and the overall procedure was repeated until no filtrate could be pulled through the apparatus. The dried membrane was sandwiched between two translucent Nafion EW 920 (RTM: PFSA-SO2F) films (0.5-1 mil in thickness), placed between two chrome-plated aluminum plates covered with non-stick aerosol spray, and positioned centrally in a hot press at 240 degrees C. The plates were hot pressed at 240 degrees C and contact pressure for 5 minutes, then 1 minute at 4000 psi and 1 minute at 8000 psi. The plates were removed and cooled to room temperature at 8000 psi. The translucent membranes were acidified. The translucent membranes were soaked in 2 M potassium hydroxide (35 ml) and dimethylsulfoxide (10 ml) at room temperature for 1 day. The translucent membranes were soaked in water for 2 hours and acidifying in 1M sulfuric acid for 1 day. The translucent membranes were then soaked in water for 2 hours and air dried. The membrane had a final composition of 10% ePTFE, 1% primer and 89% ion exchange material.