TRANSIENT CAVITIES IN LIQUIDS AND THE NATURE OF THE HYDROPHOBIC EFFECT

The size distributions of transient cavities in water and organic liqu ids, obtained ii om computer simulations, have provided a new means to analyze the nature of the hydrophobic effect and to evaluate the adeq uacy of different analytical models of this effect. The poor solubilit y of non-polar solutes in water is attributed to a low probability of finding in water cavities of atomic and molecular size. It has been sh own that water applies more force per unit area of cavity surface than do hydrocarbon liquids. Models that successfully capture the main cha racteristics of the hydrophobic effect must at least include informati on about the density and the radial distribution of oxygen atoms in li quid water. One such model, quantitatively accurate for molecular solu tes of arbitrary shape, is presented.