Understanding Hydrophobic Effects In Interfacial Environments

Solid-water interfaces, including those of proteins and membranes, are ubiquitous in the crowded cellular environment. Using molecular simulations and theory, we investigate the manifestations of the hydrophobic effect in these interfacial environments. Specifically, we quantify the hydration thermodynamics of hydrophobic solutes, with sizes ranging from sub-nanometer to a few nanometers, both in bulk water, and near self-assembled monolayers (SAMs) with a range of chemistries, from hydrophilic to hydrophobic. Our results shed light on the thermodynamics of hydrophobically-driven assembly in bulk and at interfaces, as well as that of binding to these interfaces. In particular, the driving force for assembly decreases with increasing temperature near hydrophobic surfaces, in contrast to that in bulk water. Our results also show that hydrophobic forces of assembly in the vicinity of an extended hydrophobic surface are weaker than those in bulk aqueous solution, suggesting a catalytic role for extended hydrophobic interfaces in the unfolding of proteins.