Hydrophobicity in modified water models

Molecular level explanation of the poor solubility in water of nonpolar species is still a debated topic. Recently, Lynden-Bell and Head-Gordon [R.M. Lynden-Bell, T. Head-Gordon, Mol. Phys. 104 (2006) 3593] have compared in detail, at room temperature and atmospheric pressure, the hydrophobicity of suitably modified water models with that of the realistic SPC/E water model. It is shown that, by using the effective size of liquid molecules and the experimental density of water, scaled particle theory calculations reproduce satisfactorily the results of Lynden-Bell and Head-Gordon. Hydrophobicity is mainly determined by a trade-off between the effect of the small size of water molecules and the effect of the low value of its volume packing density.