中性子超小角散乱法による放射線架橋,グラフト反応を利用して作製した架橋PTFE電解質膜の階層構造のその場観察

In situ observation for hierarchical structures of radiation crosslinked- and grafted- PTFE-g-polystyrene electrolyte membrane by ultra-small-angle neutron scattering

岩瀬 裕希; 小泉 智; 橋本 竹治; 八巻 徹也; 澤田 真一; 前川 康成

Iwase, Hiroki; Koizumi, Satoshi; Hashimoto, Takeji; Yamaki, Tetsuya; Sawada, Shinichi; Maekawa, Yasunari

本発表では、放射線グラフト重合法を活用して作製された架橋ポリテトラフルオロエチレン(PTFE)電解質膜の作製プロセスにおける構造変化、及び膨潤した状態の階層構造を中性子小角散乱法で測定した結果を報告する。さらにコントラストバリエーション法を活用することで、架橋PTFE電解質膜を形成するPTFE領域、及びグラフト鎖領域の構造情報をそれぞれ分離することに成功した。これにより電気伝導度と直接関係するイオン交換容量の変化に依存して、イオンチャンネル形成を担うグラフト鎖の構造が変化する様子を捉えることに成功した。

By using ultra-small-angle neutron scattering (USANS) techniques, we have investigated the hierarchical structures of the crosslinked-polytetrafluoroethylene (PTFE) electrolyte membrane, which is made by using both radiation-crosslinking and radiation-induced grafting of styrene, in order to reveal the correlation between the hierarchical structure and a proton conducting mechanism. We observed structural changes of crosslinking PTFE electrolyte membrane in each synthetic process and compared the structures between the crosslinking PTFE electrolyte membrane and Nafion112 under swollen state. We detected each efects of radiation crosslinking and grafting, respectively on the scattering profiles. Scattering profile for swollen crosslinking PTFE electrolyte membrane in DO has a no peak around =0.12 . where scattering profile for Nafion has a peak reflected the ion-cluster structure. However, a shoulder-like profile is appeared clearly at . This peak-position is agreement with that observed in the scattering profile after radiation-crosslinking process. The presented results suggested that the structure formed by the radiation-crosslinking is close relation with the proton conductivity for the crosslinking PTFE electrolyte membrane.