Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid
Polymer/ionic liquid systems are being increasingly explored, yet those exhibiting lower critical solution temperature (LCST) phase behavior remain poorly understood. Poly(benzyl methacrylate) in certain ionic liquids constitute unusual LCST systems, in that the second virial coefficient (<i>A...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/16/4850 |
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| author | Brian R. Carrick Claire L. Seitzinger Timothy P. Lodge |
| author_facet | Brian R. Carrick Claire L. Seitzinger Timothy P. Lodge |
| author_sort | Brian R. Carrick |
| collection | DOAJ |
| description | Polymer/ionic liquid systems are being increasingly explored, yet those exhibiting lower critical solution temperature (LCST) phase behavior remain poorly understood. Poly(benzyl methacrylate) in certain ionic liquids constitute unusual LCST systems, in that the second virial coefficient (<i>A</i><sub>2</sub>) in dilute solutions has recently been shown to be positive, indicative of good solvent behavior, even above phase separation temperatures, where <i>A</i><sub>2</sub> < 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. |
| first_indexed | 2024-03-10T08:33:20Z |
| format | Article |
| id | doaj.art-8ff04bee8af543409cc6437ecb3a4a8d |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T08:33:20Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-8ff04bee8af543409cc6437ecb3a4a8d2023-11-22T08:52:53ZengMDPI AGMolecules1420-30492021-08-012616485010.3390/molecules26164850Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic LiquidBrian R. Carrick0Claire L. Seitzinger1Timothy P. Lodge2Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USADepartment of Chemistry, University of Minnesota, Minneapolis, MN 55455, USADepartment of Chemistry, University of Minnesota, Minneapolis, MN 55455, USAPolymer/ionic liquid systems are being increasingly explored, yet those exhibiting lower critical solution temperature (LCST) phase behavior remain poorly understood. Poly(benzyl methacrylate) in certain ionic liquids constitute unusual LCST systems, in that the second virial coefficient (<i>A</i><sub>2</sub>) in dilute solutions has recently been shown to be positive, indicative of good solvent behavior, even above phase separation temperatures, where <i>A</i><sub>2</sub> < 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.https://www.mdpi.com/1420-3049/26/16/4850ionic liquidpolymerspoly(benzyl methacrylate)LCSTphase diagram |
| spellingShingle | Brian R. Carrick Claire L. Seitzinger Timothy P. Lodge Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid Molecules ionic liquid polymers poly(benzyl methacrylate) LCST phase diagram |
| title | Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid |
| title_full | Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid |
| title_fullStr | Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid |
| title_full_unstemmed | Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid |
| title_short | Unusual Lower Critical Solution Temperature Phase Behavior of Poly(benzyl methacrylate) in a Pyrrolidinium-Based Ionic Liquid |
| title_sort | unusual lower critical solution temperature phase behavior of poly benzyl methacrylate in a pyrrolidinium based ionic liquid |
| topic | ionic liquid polymers poly(benzyl methacrylate) LCST phase diagram |
| url | https://www.mdpi.com/1420-3049/26/16/4850 |
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