Influence of Anions on Proton-Conducting Membranes Based on Neutralized Nafion 117, Triethylammonium Methanesulfonate, and Triethylammonium Perfluorobutanesulfonate. 2. Electrical Properties

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• 作者：Vito Di Noto ; Matteo Piga ; Guinevere A. Giffin ; Sandra Lavina ; Eugene S. Smotkin ; Jean-Yves Sanchez ; Cristina Iojoiu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：1370-1379
• 全文大小：603K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

The electrical properties of a Nafion proton exchange membrane change dramatically when neutralized and then doped with a proton-conducting ionic liquid (PCIL). Broadband electric spectroscopy elucidates the molecular relaxation and polarization phenomena of neutralized Nafion (nN117) doped with triethylammonium methanesulfonate (TMS) and triethylammonium perfluorobutanesulfonate (TPFBu) ionic liquids. These data, coupled with those of part 1 suggest proton conduction mechanisms for both the pure PCILs and in PCIL-doped nN117. At 130 掳C, the PCILs have conductivities of 蟽_TMS = 1.4 脳 10^鈥?聽S/cm and 蟽_TPFBu = 9 脳 10^鈥?聽S/cm, while correspondingly doped nN117 have conductivities of 蟽_NTMS = 6.1 脳 10^鈥? S/cm and 蟽_NTPFBu = 1.8 脳 10^鈥?聽S/cm. The pure PCILs show three interfacial polarizations associated with proton transfer mechanisms above the melting point. PCIL-doped nN117 also has three interfacial polarizations that depend on the nanostructure characteristics of the PCIL sorbed within the nN117 polar domains. Below the PCIL melting point, doped nN117 has two dielectric relaxations, 伪 and 尾, associated with dipolar relaxations involving both the sorbed PCILs and the ionomer matrix. The data indicate a long-range charge transfer process that occurs through proton exchange between cationic clusters. Segmental motion of the polymer chains and the molecular dimensions of the ionic liquid nanoaggregates mediate this charge transfer.