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Ion conduction and phase morphology in sulfonate copolymer ionomers based on ionic liquid–sodium cation mixtures

journal contribution
posted on 01.01.2014, 00:00 authored by S Noor, Daniel Gunzelmann, J Sun, D MacFarlane, Maria ForsythMaria Forsyth
A series of sulfonate based copolymer ionomers based on a combination of ionic liquid and sodium cations have been prepared in different ratios. This system was designed to improve the ionic conductivity of ionomers by partially replacing sodium cations with bulky cations that are less associated with anion centres on the polymer backbone. This provides more conduction sites for sodium to ‘hop’ to in the ionomers. Characterization showed the glass transition and 15N chemical shift of the ionomers did not vary significantly as the amount of Na+ varied, while the ionic conductivity increased with decreasing Na+ content, indicating conductivity is increasingly decoupled from Tg. Optical microscope images showed phase separation in all compositions, which indicated the samples were inhomogeneous. The introduction of low molecular weight plasticizer (PEG) reduced the Tg and increased the ionic conductivity significantly. The inclusion of PEG also led to a more homogeneous material.

History

Journal

Journal of materials chemistry A

Volume

2

Issue

2

Pagination

365 - 374

Publisher

Royal Society of Chemistry

Location

London, Eng.

ISSN

2050-7496

Language

eng

Publication classification

C1 Refereed article in a scholarly journal; C Journal article

Copyright notice

2014, Royal Society of Chemistry