Kosmotropic effect leads to LCST decrease in thermoresponsive polymer solutions
Swaminath Bharadwaj1, P B Sunil Kumar2, Shigeyuki Komura3
1Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
The Journal of Chemical Physics
|March 3, 2018
Summary
Adding kosmotropic cosolvents decreases the lower critical solution temperature (LCST) in polymer solutions by reducing solvent energy. This effect lessens with increased polymer hydrophilicity, explaining LCST behavior in specific systems.
Area of Science:
- Physical Chemistry
- Polymer Science
- Computational Chemistry
Background:
- Thermoresponsive polymers exhibit a lower critical solution temperature (LCST), a key characteristic for their applications.
- Understanding the influence of cosolvents on polymer solution thermodynamics is crucial for material design.
Purpose of the Study:
- To investigate the mechanism behind the decrease in LCST upon addition of kosmotropic cosolvents.
- To elucidate the role of polymer hydrophilicity in modulating the cosolvent effect on LCST.
Main Methods:
- Employed explicit solvent coarse-grained simulations.
- Utilized mean-field theory with the Kolomeisky-Widom solvophobic potential.
- Analyzed the energetic contributions of polymer-solvent and solvent-solvent interactions.
Main Results:
- Demonstrated that reduced bulk solvent energy, induced by cosolvents, drives the decrease in LCST.
- Quantified the diminished impact of cosolvents on LCST with increasing polymer hydrophilicity.
- Explained the absence of LCST decrease in specific polymer-water-methanol systems.
Conclusions:
- A mean energetic representation is sufficient to understand LCST decrease phenomena in polymer solutions.
- The study provides insights into tuning polymer solution behavior through cosolvent addition.
- Findings contribute to the rational design of advanced thermoresponsive materials.
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