Polytetrafluoroethylene-based proton-conducting membranes prepared by ultraviolet-induced photografting

Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru

A novel process comprising UV-induced photografting of styrene into PTFE films and subsequent sulfonation has been developed for preparing proton-conducting membranes. The significance of this process is that the graft chains can penetrate throughout the PTFE base films; the resultant sulfonated electrolyte membrane with a low degree of grafting near 7% shows higher proton conductibility and better mechanical properties, similar to those of Nafion membrane. Furthermore, the performances of the UV-photografted electrolyte membranes are better as compared to those of the radiation grafted electrolyte membranes.