Cavity thermodynamics and hydrophobicity

We emphasize that the thermodynamics of cavity creation in a liquid is well established on statistical mechanical grounds. Theoretical relations demon strate that the Gibbs energy cost to create a cavity is due to the excluded volume effect arising from the selection of the constrained molecular conf igurations possessing the cavity in the full statistical ensemble of the pu re solvent. The enthalpic cost of cavity creation is exactly compensated by a. corresponding entropic gain: rupture of intermolecular interactions rai ses the energy of the solvent molecules and their degrees of freedom in a c ompensating manner. These fundamental points ale used tu interpret the resu lts of scaled particle theory calculations in different solvents and to pro vide a molecular explanation for hydrophobicity.