SIZE DEPENDENCE OF THE SOLVATION FREE-ENERGIES OF LARGE SOLUTES

The solvation Gibbs free energy of linear molecules is shown to be a l inear function of the length, or number of units, of the molecule when this length exceeds the correlation length of the solute due to the s olvent. For large molecules in simple solvents, the solvation Gibbs en ergy, in leading order, scales as the solute volume, not the solute su rface area, as might bc expected. The solvation Gibbs energy, as deter mined from experimental measurements on solute concentrations in coexi sting phases, needs no correction due to solute-solvent size ratio. A critique of a recent assertion to the contrary is presented.