Non-monotonic dependence of water reorientation dynamics on surface hydrophilicity: Competing effects of the hydration structure and hydrogen-bond strength

Guillaume Stirnemann, Santiago Romero Vargas Castrillón, James T. Hynes, Peter J. Rossky, Pablo G. Debenedetti, Damien Laage

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

The reorientation dynamics of interfacial water molecules was recently shown to change non-monotonically next to surfaces of increasing hydrophilicity, with slower dynamics next to strongly hydrophobic (apolar) and very hydrophilic surfaces, and faster dynamics next to surfaces of intermediate hydrophilicities. Through a combination of molecular dynamics simulations and analytic modeling, we provide a molecular interpretation of this behavior. We show that this non-monotonic dependence arises from two competing effects induced by the increasing surface hydrophilicity: first a change in the hydration structure with an enhanced population of water OH bonds pointing toward the surface and second a strengthening of the water-surface interaction energy. The extended jump model, including the effects due to transition-state excluded volume and transition-state hydrogen-bond strength, provides a quasi-quantitative description of the non-monotonic changes in the water reorientation dynamics with surface hydrophilicity.

Original languageEnglish (US)
Pages (from-to)19911-19917
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number44
DOIs
StatePublished - Nov 28 2011

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