On the influence of solute polarizability on the hydrophobic interaction.

The authors have performed molecular dynamics simulations of polarizable solutes in water to investigate how solute polarizability affects solute-solute hydrophophic interactions. A degree of polarization similar to the one expected in biomolecules, corresponding to a dielectric response of epsilon=2-20, results in dramatic changes in the hydrophobic forces. They find that this degree of polarizability is enough to inhibit drying between hydrophobic solutes and to stabilize a reduced water density phase whose density is smaller than the bulk water density. The hydrophobic forces associated with such reduced density states are still very significant with values of the order of several tens of piconewtons. Their results suggest that polarizability plays an important role in determining the hydrophobic force acting between weakly polar surfaces.