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.