Unusual lower critical solution temperature phase behavior of poly(Benzyl methacrylate) in a pyrrolidinium-based ionic liquid

Brian R. Carrick, Claire L. Seitzinger, Timothy P. Lodge

Research output: Contribution to journalArticlepeer-review

Abstract

Polymer/ionic liquid systems are being increasingly explored, yet those exhibiting lower critical solution temperature (LCST) phase behavior remain poorly understood. Poly(benzyl methacry-late) in certain ionic liquids constitute unusual LCST systems, in that the second virial coefficient (A2 ) in dilute solutions has recently been shown to be positive, indicative of good solvent be-havior, even above phase separation temperatures, where A2 < 0 is expected. In this work, we describe the LCST phase behavior of poly(benzyl methacrylate) in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide for three different molecular weights (32, 63, and 76 kg/mol) in concentrated solutions (5–40% by weight). Turbidimetry measurements reveal a strong concentration dependence to the phase boundaries, yet the molecular weight is shown to have no influence. The critical compositions of these systems are not accessed, and must therefore lie above 40 wt% polymer, far from the values (ca. 10%) anticipated by Flory-Huggins theory. The proximity of the experimental cloud point to the coexistence curve (binodal) and the thermo-reversibility of the phase transitions, are also confirmed at various heating and cooling rates.

Original languageEnglish (US)
Article number4850
JournalMolecules
Volume26
Issue number16
DOIs
StatePublished - Aug 11 2021

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation (Awards DMR-1707578 and DMR-2103630), University of Minnesota?s Office of Undergraduate Research, and the University of Minnesota?s Department of Chemistry Summer Research Fellowship.

Funding Information:
Funding: This work was supported by the National Science Foundation (Awards DMR-1707578 and DMR-2103630), University of Minnesota’s Office of Undergraduate Research, and the University of Minnesota’s Department of Chemistry Summer Research Fellowship.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Ionic liquid
  • LCST
  • Phase diagram
  • Poly(benzyl methacrylate)
  • Polymers

PubMed: MeSH publication types

  • Journal Article

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