Rheological scaling of ionic-liquid-based polyelectrolytes in ionic liquid solutions: the effect of the ion diameter of ionic liquids

Atsushi Matsumoto, Amy Q. Shen

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We investigate the effect of the ion diameter a of ionic liquids (ILs) on the shear viscosity of polymerized ionic liquids (PILs) in IL solutions. When both the PIL and IL contain large PFSI anions (a ≈ 0.57 nm), the specific viscosity ηsp first decreases with increasing IL concentration cIL in the low cIL regime, reaches a minimum and then increases with increasing cIL in the high cIL regime. By comparing the measured ηsp with the modified charge screening model proposed in our previous study [Matsumoto et al., Macromolecules, 2021, 54, 5648-5661], we attribute the observed non-monotonic trend of ηsp against cIL to the charge underscreening phenomenon, i.e., an increase of the screening length at high cIL leads to the upturn of ηsp. On the other hand, when the PIL and IL contain small BF4 anions (a ≈ 0.34 nm), the ηsp decreases asymptotically with increasing cIL, because the charge on the PIL chain is likely screened fully in the entire cIL regime. Our results demonstrate that the ion diameter of ILs plays an important role in governing the charge screening mechanism of PILs in IL solutions, and thus influencing the viscoelastic properties of PIL solutions.

Original languageEnglish (US)
Pages (from-to)4197-4204
Number of pages8
JournalSoft Matter
Volume18
Issue number21
DOIs
StatePublished - Jun 1 2022

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics

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