Influence of co-non-solvency on hydrophobic molecules driven by excluded volume effect.

We demonstrate by molecular dynamics simulation that co-non-solvency manifests itself in the solvent-induced interaction between three hydrophobes, methane, propane and neopentane, in methanol-water mixtures. Decomposition of the potential of mean force, based on the potential distribution theorem, clearly shows that the solute-solvent entropic change is responsible for stabilizing the aggregation of these hydrophobic molecules. Furthermore, we show that the entropic change pertains to the excluded volume effect.