THE HYDROPHOBIC EFFECT - 1 - A CONSEQUENCE OF THE MOBILE ORDER IN H-BONDED LIQUIDS

The hydrophobic effect has an entropic nature that cannot be explained by classical multicomponent treatments that do not explicitly take in to account both the mobility and the nonergodicity of the H-bonds in a mphiphilic liquids. The nonergodic thermodynamics of mobile order in H -bonded liquids based on time fractions rather than on concentrations provides a novel qualitative and quantitative explanation for the mole cular origin of the hydrophobic effect. Chiefly, this effect correspon ds to the loss of the mobile order entropy of associated molecules by dilution with foreign substances. Not being a unique property of water , the propensity of an amphiphilic solvent to induce a solvophobic eff ect increases primarily as its structuration factor increases, and sec ondarity as the solute/solvent molar volume ratio increases. On this b asis, it can be expected that in the absence of strong solute-solvent specific interactions, the solubility of nonelectrolytes will generall y decrease in the following order: butanol > propanol > ethanol > meth anol > propylene glycol > ethylene glycol > formamide > water.