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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 16: Modeling and Simulation of Soft Matter II
CPP 16.9: Talk
Tuesday, March 19, 2024, 12:00–12:15, H 0106
Solvation Shell Thermodynamics of Extended Hydrophobic Solutes — •Madhusmita Tripathy1, Swaminath Bharadwaj1, 2, and Nico van der Vegt1 — 1Department of Chemistry, TU Darmstadt, Darmstadt, Germany 64297 — 2Department of Chemical Engineering, Shiv Nadar University, Delhi-NCR, India 201314
Interfacial solvent density fluctuations play an important role in hydrophobic effects, which regulate the functional characteristics of a wide variety of soft matter systems. The loss of water hydrogen bonds near large non-polar solutes leads to enhanced density fluctuations, which make their hydration shells susceptible to small perturbations. Cosolutes can regulate the solute’s hydration behavior by enhancing/quenching these fluctuations. To understand the underlying molecular mechanisms, we employ computer simulation to investigate the effect of two adsorbing cosolutes, urea and methanol, on the interfacial thermodynamics of a model extended hydrophobic solute. We find that urea accumulation quenches the interfacial fluctuations, leading to a decrease in the solvation shell compressibility, while methanol accumulation enhances the fluctuations, leading to an increase in compressibility[1]. Analyses on solvation shells energetics indicates that the effect of these adsorbing cosolutes on the density fluctuations, and thereby the stability of the solvation shell, is strongly coupled to their hydration behavior. The observations from this simple model can be discussed in the context of cosolute induced swelling and collapse of polymers in aqueous solutions.
1. M. Tripathy et al. J.Chem.Phys. 2022, 156, 164901
Keywords: Preferential Adsorption; Hydrophobic Interaction; Interfacial Density Fluctuation; Solvation Thermodynamics