Polycation radius of gyration in a polymeric ionic liquid (PIL): The PIL melt is not a theta solvent

Lucas N. Wong, Seamus D. Jones, Kathleen Wood, Liliana De Campo, Tamim Darwish, Michael Moir, Hua Li, Rachel A. Segalman, Gregory G. Warr, Rob Atkin

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The conformation of the polycation in the prototypical polymeric ionic liquid (PIL) poly(3-methyl-1-aminopropylimidazolylacrylamide) bis(trifluoromethylsulfonyl)imide (poly(3MAPIm)TFSI) was probed using small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) at 25 °C and 80 °C. Poly(3MAPIm)TFSI contains microvoids which lead to intense low q scattering that can be mitigated using mixtures of hydrogen- and deuterium-rich materials, allowing determination of the polycation conformation and radius of gyration (Rg). In the pure PIL, the polycation adopts a random coil conformation with Rg = 52 ± 0.5 Å. In contrast to conventional polymer melts, the pure PIL is not a theta solvent for the polycation. The TFSI- anions, which comprise 48% v/v of the PIL, are strongly attracted to the polycation and act like small solvent molecules which leads to chain swelling analogous to an entangled, semi-dilute, or concentrated polymer solution in a good solvent.

Original languageEnglish
Pages (from-to)4526-4532
Number of pages7
JournalPhysical Chemistry Chemical Physics
Issue number7
Publication statusPublished - Feb 2022


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