Transient Cavities in Liquids and the Nature of the Hydrophobic Effect

Andrew Pohorille

Exobiology Branch
NASA -- Ames Research Center
MS 239-4
Moffett Field, California 94035-1000

Department of Pharmaceutical Chemistry,
University of California, San Francisco,
San Francisco, California 94143

Abstract:

The size distributions of transient cavities in water and other organic liquids, obtained from computer simulations, have provided a new means to analyze the nature of the hydrophobic effect and to evaluate the adequacy of different analytical models of this effect. The poor solubility 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 shown that water applies more force per unit area of cavity surface than do hydrocarbon liquids. Models that successfully capture the main characteristics of the hydrophobic effect must at least include information about the density and the radial distribution of oxygen atoms in liquid water. One such model, quantitatively accurate for molecular solutes of arbitrary shape, is presented.

 

	Introduction
	Basic Theory and Methodology
	Cavity Statistics in Water and Other Organic Liquids
	Beyond Cavity Statistics - A Two-moment Model of the Hydrophobic Effect
	Conclusions
	References
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