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DY: Fachverband Dynamik und Statistische Physik

DY 41: Modeling and Simulation of Soft Matter II (joint session CPP/DY)

DY 41.8: Vortrag

Donnerstag, 4. April 2019, 11:45–12:00, H13

Cononsolvency of thermoresponsive polymers: theory and simulation — •Nico van der Vegt, Swaminath Bharadwaj, Cahit Dalgicdir, and Divya Nayar — Technische Universität Darmstadt, Germany

Cononsolvency of thermoresponsive polymers is an intriguing phenomenon whose molecular-scale mechanism remains elusive ever since it was first reported in the late 1980s. I will present theoretical results and computer simulations which provide a new angle on this question. Significantly, direct cosolvent binding to the polymer is shown to be an entropy-driven process, which leads to polymer dehydration resulting in coil-globule collapse and phase separation in poly(N-isopropyl acrylamide)/water/methanol solutions. Specific cosolvent interactions with the polymer play no role in this mechanism. Instead of that, cosolvent enrichment around hydrophobic groups frustrates hydration of the amide group and induces phase separation. Theoretical arguments and simulation results are furthermore presented which illustrate that direct cosolvent binding is not a necessary requirement for cononsolvency.

D. Nayar, N.F.A. van der Vegt, J. Phys. Chem. B 122, 3587-3595 (2018) N.F.A. van der Vegt, D. Nayar, J. Phys. Chem. B 121, 9986-9998 (2017) C. Dalgicdir, F. Rodriguez-Ropero, N.F.A. van der Vegt, J. Phys. Chem. B 121, 7741-7748 (2017)