Creation of anisotropically conducting electrolyte membranes using ion beam nano-fabrication technique

Maekawa, Yasunari; Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru

no journal, , 

Two approaches using swift ion beams have been examined for the preparation of polymer electrolyte membranes (PEM). The first method utilizes the latent tracks, in which polystyrene (PSt) is directly grafted into the latent tracks of poly(ethylene-co-tetrafluoroethylene) (ETFE) films and, in consequence, the grafted PSt is sulfonated. The second method utilizes the ion etched tracks; the latent tracks are etched out and then PSt is deposited into the etched pores, followed by the sulfonation of the grafted PSt. These method leads to the anisotropically conducting PEM, consisting of highly conductive cylindrical layers with 200-300 nm in diameter surrounded by a thermally stable matrix region. Especially, the latent track PEM achieved less water uptake, higher gas barrier property, and higher tensile strengths at break at the same time, compared to conventional grafted PEMs with the same IEC prepared by g-rays irradiation.