Proton conductivity of sulfonated long-chain-block copolyimide films

Abstract

We have synthesized a novel sulfonated block copolyimide with long block chains by chemical imidization using a two-pot procedure. The proton conductivity of a block copolyimide film, i.e., NTDA-BDSA-b-6FAP (140/ 60) was approximately 0.45 S cm-1, which is higher than that of Nafion117®. Additionally, we demonstrated that the proton conductivity of the block copolyimide film strongly depends on the block chain lengths. The conductivities of the block copolyimide films increased with increasing block chain lengths. This may be due to the formation of ionic channels in the copolyimide films and its dependence on the block chain length. We are currently investigating the effects of the morphology and domain size of the block copolyimide film on the proton conductivity.