Analysis of hierarchical structure of ETFE-based graft-type polymer electrolyte membranes by small angle X-ray scattering

Tran, D. T.; Sawada, Shinichi; Hasegawa, Shin; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari

We investigated the hierarchical structures of poly(ethylene-co-tetrafluoroethylene) (ETFE) based polymer electrolyte membranes (ETFE-PEMs) by comparison with those of precursor original ETFE and styrene-grafted (grafted ETFE) films using small-angle X-ray scattering (SAXS). The ETFE substrate has a lamellar structure with d-spacing of 23.1 nm, while grafted ETFE and ETFE-PEMs showed shoulder peaks at lower Q values, corresponding to d-spacing of 32.7 and 36.1 nm. The grafted ETFE and ETFE-PEM showed new peaks at larger Q value regions, corresponding to d-spacing of 0.94 and 1.48 nm, respectively. These peaks should be ascribed to internal structures of grafted polymers and ion channels.