Molecular Design and Characterization of Ionic Monomers with Varying Ion Pair Interaction Energies

Ryosuke Matsuno, Yota Kokubo, Shinji Kumagai, Shigeaki Takamatsu, Kazunobu Hashimoto, Atsushi Takahara

Research output: Contribution to journalArticle

Abstract

Ionic liquid monomers with ion pair interaction energies ranging from 73.0 to 101.4 kcal/mol were designed by using the calculated electrostatic potential (ESP) values of the component ions. The ionic liquid monomers were classified as cationic monomers with an anionic counterion and anionic monomers with a cationic counterion. We evaluated the calculated ion pair interaction energy using counterion mobility as an indicator. One component of the ion pair was fixed onto a dielectric elastomer by using alkoxysilane coupling agents, while the counterion remained free to move under the applied voltage. We then measured the relative dielectric constant at 0.01 Hz, which is an indicator of the mobility of the counterion. The results showed a good correlation between the calculated ion pair interaction energy and the relative dielectric constant. The lower the ion pair interaction energy is, the easier the dissociation of the ion pair. From this result, we were able to prove the correlation between the calculated ion pair interaction energy and the mobility of the counterion. Furthermore, classification of other ion pair compounds and polyelectrolyte polymer brushes that follow the anion Hofmeister series based on ion pair interaction energies revealed the correlation between physical properties and the ionic structure. Various ionic compounds with desired physical properties can be designed by using the calculated ion pair interaction energies.

Original languageEnglish
JournalMacromolecules
DOIs
Publication statusAccepted/In press - Jan 1 2020

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All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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