Entropy convergence in hydrophobic hydration: a scaled particle theory analysis

The occurrence of entropy convergence in hydrophobic hydration is verified from available experimental thermodynamic data for both noble gases and hydrocarbons. The entropy convergence phenomenon can be reproduced by means of the scaled particle theory, provided that a temperature-dependent hard sphere diameter is used for water molecules. The calculated work of cavity creation shows a non-monotonic temperature dependence with a flat maximum slightly above 100 degreesC, irrespective of the cavity size. The corresponding cavity entropy changes converge approximately 100 degreesC, in qualitative agreement with the experimental finding. (C) 2003 Elsevier Science B.V. All rights reserved.