EFFECTS OF SOLVENT-CASTING CONDITIONS ON THE MORPHOLOGY AND PROPERTIES OF HIGHLY FLUORINATED POLY (ARYLENE ETHERSULFONE) COPOLYMER FILMS FOR POLYMER ELECTROLYTE MEMBRANES

摘要

Poly(arylene ether sulfone) block copolymers are studied as candidates for membrane materials in polymer electrolyte membrane fuel cells. Highly-fluorinated versions are of particular interest as increase hydrophobicity of the fluorinated blocks will induce greater phase separation resulting in improved proton conductivity. This work studies the effect of processing temperature on membrane properties and compares results for highly-fluorinated poly(arylene ether sulfones) to results for the sparingly fluorinated copolymer. Proton conductivities are below the expected values, which is likely due to high processing temperatures having detrimental effects on ion clusters in copolymer chain coupled with a lack of ample time for phase separation. Studies of the phase separation kinetics and final film morphologies can help better understand the drying process.