Molecular Mobility and Cation Conduction in Polyether鈥揈ster鈥揝ulfonate Copolymer Ionomers

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• 作者：Gregory J. Tudryn ; Michael V. O鈥橰eilly ; Shichen Dou ; Daniel R. King ; Karen I. Winey ; James Runt ; 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：3962-3973
• 全文大小：700K
• 年卷期：v.45,no.9(May 8, 2012)
• ISSN：1520-5835

文摘

Poly(ethylene oxide) [PEO] ionomers are candidate materials for electrolytes in energy storage devices due to the ability of ether oxygen atoms to solvate cations. Copolyester ionomers are synthesized via condensation of sulfonated phthalates with glycol mixtures of PEO and poly(tetramethylene oxide) [PTMO] to create random copolymer ionomers with nearly identical ion content and systematically varying solvation ability. Variation of the PEO/PTMO composition leads to changes in T_g, dielectric constant and ionic aggregation; each with consequences for ion transport. Dielectric spectroscopy is used to determine number density of conducting ions, their mobility, and extent of aggregation. Conductivity and mobility display Vogel temperature dependence and increase with PEO content; despite the lower T_g of PTMO. Conducting ion densities show Arrhenius temperature dependence and are nearly identical for all copolymer ionomers that contain PEO. SAXS confirms the extent of aggregation, corroborates the temperature response from dielectric measurements, and reveals microphase separation into a PTMO-rich microphase and a PEO-rich microphase that contains the majority of the ions. The trade-off between ion-solvation and low T_g in this study provides fundamental understanding of ionic aggregation and ion transport in polymer single-ion conductors.