Synthesis and Transport Properties of Proton-Conducting Membranes Based on Polyvinylidene Fluoride Films with Introduced and Sulfonated Polystyrene

Thermal polymerization of styrene sorbed into a polyvinylidene fluoride (PVdF) film from a toluene solution followed by sulfonation of the resulting material was performed. The kinetics of polystyrene (PS) accumulation in the PVdF film during thermal polymerization was studied. Samples with 6-30 wt % PS and similar to 100% PS sulfonation were obtained. Proton-exchange membranes wsith an ion-exchange capacity of up to 2 mg-eq/g and proton conductivity of up to 0.008 S/cm at 75% relative humidity were prepared. The permeability coefficients of water, methanol, and hydrogen and their dependences on the amount of introduced PS, ion-exchange capacity, and water uptake of membranes were measured. The synthesized materials proved similar to MF-4SK membranes in their basic transport characteristics and can be used as proton-exchange membranes in hydrogen-air and alcohol fuel cells.