Thermally driven ionic aggregation in poly(ethylene oxide)-based sulfonate ionomers

Wenqin Wang, Gregory J. Tudryn, Ralph H. Colby, Karen I. Winey

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Abstract

A series of sulfonate polyester ionomers with well-defined poly(ethylene oxide) spacer lengths between phthalates and alkali metal cations as counterions are designed for improved ionic conductivity. Ion conduction in these chemically complex materials is dominated by the polymer mobility and the state of ionic aggregation. While the aggregation decreases dramatically at room temperature as the cation size increases from Li to Na to Cs, the extents of ionic aggregation of these ionomers are comparable at elevated temperatures. Both the Na and Cs ionomers exhibit thermally reversible transformation upon heating from 25 to 120 °C as isolated ion pairs aggregate. This seemingly counterintuitive aggregation of ions on heating is driven by the fact that the dielectric constant of all polar liquids decreases on heating, enhancing Coulomb interactions between ions.

Original languageEnglish (US)
Pages (from-to)10826-10831
Number of pages6
JournalJournal of the American Chemical Society
Volume133
Issue number28
DOIs
StatePublished - Jul 20 2011

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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