Statistical analyses of hydrophobic interactions: A mini-review

TL;DR

This mini-review summarizes recent advances in understanding hydrophobic interactions, highlighting inverse temperature behavior, effects of attractive forces, and the importance of molecular theories for accurate interpretation.

Contribution

It presents new insights into hydrophobic interactions, emphasizing the inverse temperature phenomenon and the role of attractive forces, with evaluation of molecular theories for corrections.

Findings

Hydrophobic interactions strengthen with increasing temperature.

Adding attractive forces weakens hydrophobic bonds.

Molecular quasi-chemical theory shows promise for corrections.

Abstract

This review focuses on the striking recent progress in solving for hydrophobic interactions between small inert molecules. We discuss several new understandings. Firstly, the _inverse _temperature phenomenology of hydrophobic interactions, _i.e., strengthening of hydrophobic bonds with increasing temperature, is decisively exhibited by hydrophobic interactions between atomic-scale hard sphere solutes in water. Secondly, inclusion of attractive interactions associated with atomic-size hydrophobic reference cases leads to substantial, non-trivial corrections to reference results for purely repulsive solutes. Hydrophobic bonds are _weakened by adding solute dispersion forces to treatment of reference cases. The classic statistical mechanical theory for those corrections is not accurate in this application, but molecular quasi-chemical theory shows promise. Finally, because of the masking roles of excluded volume and attractive interactions, comparisons that do not discriminate the different possibilities face an interpretive danger.