Depression of methanol-crossover using multilayer proton conducting membranes prepared by layer-by-layer deposition onto a porous polyethylene film

A novel multilayer proton conducting membrane was fabricated using the layer-by-layer deposition technique onto the surface modified porous PE membrane. The PE-g-PSS was initially prepared by the graft polymerization of styrene onto a porous polyethylene (PE) substrate film and subsequent sulfonation reaction. The layer-by-layer stacked film was obtained by the alternative deposition of poly(vinylimidazole) (P(VIm)) and poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (P(AMPSA)). These two polymers were strongly combined by the acid-base interaction. The characteristics of the multilayer membrane, such as the proton conductivity and methanol permeability, were investigated as a function of the number of stacking layers, and were also compared with those of Nafion 115 and 117 membranes.