Surface-charged polyacrylonitrile/poly(vinyl alcohol) (PAN/PVA) colloids used to prepare proton conducting materials

Proton exchang e membranes e xhibiting a well-org anized structure were successfully prepared by a novel self-assembling technique using surface-charged latex nanoparticles as building blocks. The nanoparticles were synthesized in water by free-radical copolymerization. Free-standing membranes were obtained by casting the poly mer e mulsions followed by a cross-linking reaction. The acquired membrane exhibited a hig h proton condu ctivity of 0.04 S cm-1 with an ion exchange c apacity ( IEC) as low as 0.48 mmol g -1. The e nhanced proton conductivity is thought to be derived from the formation of a cocontinuous ionic network for i on channels by the clo sely packed surface-charged latex nanoparticles, facilitating proton transportation in the membranes.