Ion specific, odd-even glass transition temperatures and conductivities in precise network polymerized ionic liquids

Chengtian Shen, Qiujie Zhao, Christopher M. Evans

Research output: Contribution to journalArticlepeer-review

Abstract

A series of crosslinked network polymerized ionic liquids (n-PILs) were synthesized with precise linker lengths, ranging from 4-12 carbons, to investigate the role of network nanostructure and electrostatic interactions on ion transport. The n-PILs contain tethered ammonium cations and either spherical BF4 or large, non-spherical bis(trifluoromethane)sulfonimide (TFSI) mobile anions. In the TFSI networks, a pronounced odd-even effect is observed with carbon linker length where the glass transition temperature (Tg) can vary by 45 K and conductivity by almost two orders of magnitude simply by adding one carbon between the junctions. The dynamic fragility of the temperature-dependent conductivity also shows an odd-even effect. In the BF4 networks, made from the same initial network, higher Tgs are observed with no odd-even effect. Both versions of the networks exhibit ionic aggregation peaks (via wide-angle X-ray scattering) which show monotonic variations with carbon length. These findings indicate that major odd-even Tg and conductivity effects can be observed with small variations in the chemical structure.

Original languageEnglish (US)
Pages (from-to)332-341
Number of pages10
JournalMolecular Systems Design and Engineering
Volume4
Issue number2
DOIs
StatePublished - Apr 2019

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Chemical Engineering (miscellaneous)
  • Biomedical Engineering
  • Energy Engineering and Power Technology
  • Process Chemistry and Technology
  • Industrial and Manufacturing Engineering
  • Materials Chemistry

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