Chemistry

Thermoreversible ion gels from side-chain liquid crystalline brushes diblock copolymers

Document Type

Article

Abstract

We report a strategy for preparing thermoreversible ion gels from a library of liquid crystalline brush block copolymers (LCBBCs). These LCBBCs were synthesized by ring-opening metathesis polymerization (ROMP) of side-chain functionalized norbonenes comprising cholesteryl ester with nine methylene spacer and poly(ethylene glycol) monomethyl ether (MPEG). The molecular composition, thermal properties, and morphologies of these brush block copolymers were investigated. These LCBBCs were used to form ion gel via self-assembly of LCBBCs in a room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6]. The hydrophilic PEO units are soluble in IL, while the use of cholesterol allows the formation of junction in the gel network due to the insolubility of its chain in IL, which predominantly provides mechanical robustness to the corresponding ion gels. Transparent, strong ion-gels with significant mechanical strength (~103 Pa) and high ionic conductivity (~10-2 S/cm) can be formed at approximately 20 wt.% concentration of the LCBBCs. The self-assembled ion gels have tunable thermal, mechanical, and morphological properties by virtue of their architecture and functionality is an alternative and attractive way for development of novel solid state electrolytes and offer exciting possibilities of their application in electrochemical devices.

Publication Title

Functional Polymers: Design, Synthesis, and Applications

Publication Date

2017

First Page

241

Last Page

264

ISBN

9781771882972

DOI

10.1201/9781315366524

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