This content will become publicly available on March 10, 2023

Understanding Hydrophobic Effects: Insights from Water Density Fluctuations
The aversion of hydrophobic solutes for water drives diverse interactions and assemblies across materials science, biology, and beyond. Here, we review the theoretical, computational, and experimental developments that underpin a contemporary understanding of hydrophobic effects. We discuss how an understanding of density fluctuations in bulk water can shed light on the fundamental differences in the hydration of molecular and macroscopic solutes; these differences, in turn, explain why hydrophobic interactions become stronger upon increasing temperature. We also illustrate the sensitive dependence of surface hydrophobicity on the chemical and topographical patterns the surface displays, which makes the use of approximate approaches for estimating hydrophobicity particularly challenging. Importantly, the hydrophobicity of complex surfaces, such as those of proteins, which display nanoscale heterogeneity, can nevertheless be characterized using interfacial water density fluctuations; such a characterization also informs protein regions that mediate their interactions. Finally, we build upon an understanding of hydrophobic hydration and the ability to characterize hydrophobicity to inform the context-dependent thermodynamic forces that drive hydrophobic interactions and the desolvation barriers that impede them.
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Publication Date:
NSF-PAR ID:
10318585
Journal Name:
Annual Review of Condensed Matter Physics
Volume:
13
Issue:
1
ISSN:
1947-5454
5. A classical model in the framework of the INTERFACE force field has been developed for treating the LiCoO$_2$ (LCO) (001)/water interface. In comparison to {\em ab initio} molecular dynamics (MD) simulations based on density functional theory, MD simulations using the classical model lead to generally reliable descriptions of interfacial properties, such as the density distribution of water molecules. Water molecules in close contact with the LCO surface form a strongly adsorbed layer, which leads to a free energy barrier for the absorption of polar or charged molecules to the LCO surface. Moreover, due to the strong hydrogen bonding interactions with the LCO surface, the first water layer forms an interface that exhibits hydrophobic characters, leading to favorable adsorption of non-polar molecules to the interface. Therefore, despite its highly polar nature, the LCO (001) surface binds not only polar/charged but also non-polar solutes. As an application, the model is used to analyze the adsorption of reduced nicotinamide adenine dinucleotide (NADH) and its molecular components to the LCO (001) surface in water. The results suggests that recently observed redox activity of NADH at the LCO/water interface was due to the co-operativity between the ribose component, which drives binding to the LCO surface,more »