Hierarchical Structure鈥揚roperty Relationships in Graft-Type Fluorinated Polymer Electrolyte Membranes Using Small- and Ultrasmall-Angle X-ray Scattering Analysis

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• 作者：Tran Duy Tap ; Shin-ichi Sawada ; Shin Hasegawa ; Kimio Yoshimura ; Yojiro Oba ; Masato Ohnuma ; Yosuke Katsumura ; Yasunari Maekawa
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：47
• 期：7
• 页码：2373-2383
• 全文大小：740K
• 年卷期：v.47,no.7(April 8, 2014)
• ISSN：1520-5835

文摘

The hierarchical structures of graft-type poly(ethylene-co-tetrafluoroethylene) (ETFE)-based polymer electrolyte membranes (ETFE-PEMs) were investigated using small- and ultrasmall-angle X-ray scattering experiments. The ETFE-PEMs with ion exchange capacities (IECs) <2.4 mmol/g possessed conducting graft domains around lamellar crystals, with a d-spacing of 21.8鈥?9.1 nm, and oriented crystallites (lamellar grains) with short and long correlation distances of 218鈥?20 and 903鈥?124 nm, respectively. The membranes with IECs > 2.7 mmol/g showed a new phase of crystallite network domains with a d-range of 225鈥?56 nm, indicating a phase transition from oriented crystallite to crystallite network structures in the IEC range of 2.4鈥?.7 mmol/g. Noted that for the ETFE-PEMs with high IECs higher conductivity at 30% RH and compatible tensile strengths at 100% RH and 80 掳C, compared with Nafion, originated from the well-interconnected ion channels around the crystallites and the remaining lamellar crystals and crystallites, respectively.