Synthesis and Characterization of Sulfonated‐ Fluorinated, Hydrophilic‐Hydrophobic Multiblock Copolymers for Proton Exchange Membranes

Abstract

Abstract Nanophase separated ionic‐hydrophobic block copolymers may be more suitable as proton exchange membranes than random copolymers. A series of multiblock copolymers, composed of alternating segments of fully disulfonated poly(arylene ether sulfone) and highly fluorinated poly(arylene ether sulfone), were synthesized from hydrophilic and hydrophobic telechelic oligomers having a variation of molecular weights. The high reactivity of the fluorinated oligomers made unnecessary the use of high reaction temperatures, and thus the coupling reactions may be free of ether‐ether interchange side reactions. The copolymers were characterized with regard to proton conductivity, water uptake and self‐diffusion coefficient of water, and the results were compared to those of Nafion and a partially disulfonated BPSH‐35 random copolymer.