Ionic Conduction and Dielectric Response of Poly(imidazolium acrylate) Ionomers

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• 作者：U Hyeok Choi ; Minjae Lee ; Sharon Wang ; Wenjuan Liu ; Karen I. Winey ; Harry W. Gibson ; Ralph H. Colby
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：May 8, 2012
• 年：2012
• 卷：45
• 期：9
• 页码：3974-3985
• 全文大小：613K
• 年卷期：v.45,no.9(May 8, 2012)
• ISSN：1520-5835

文摘

We use X-ray scattering to investigate morphology and dielectric spectroscopy to study ionic conduction and dielectric response of imidazolium-based single-ion conductors with two different counterions [hexafluorophosphate (PF₆^{鈥?/sup>) or bis(trifluoromethanesulfonyl)imide (F₃CSO₂NSO₂CF₃鈥?/sup> = Tf₂N鈥?/sup>)] with different imidazolium pendant structures, particularly tail length (n-butyl vs n-dodecyl). A physical model of electrode polarization is used to separate ionic conductivity of the ionomers into number density of conducting ions and their mobility. Tf₂N鈥?/sup> counterions display higher ionic conductivity and mobility than PF₆鈥?/sup> counterions, as anticipated by ab initio calculations. Ion mobility is coupled to polymer segmental motion, as these are observed to share the same Vogel temperature. Ionomers with the n-butyl tail impart much larger static dielectric constant than those with the n-dodecyl tail. From the analysis of the static dielectric constant using Onsager theory, there is more ionic aggregation in ionomers with the n-dodecyl tails than in those with the n-butyl tails, consistent with X-ray scattering, which shows a much stronger ionic aggregate peak for the ionomers with dodecyl tails on their imidazolium side chains.}