Theories of Hydrophobic Effects and the Description of Free Volume in   Complex Liquids
  Recent progress on molecular theories of hydration of nonpolar solutes in aqueous solution has led to new ways of thinking about the old issue of free, or "available," volume in liquids. This article surveys the principal new results with particular attention to general issues of packing in liquids. 
Lawrence R. Pratt, Shekhar Garde, and Gerhard Hummer