We develop a unified and generally applicable theory of solvation of small and large apolar species in water. In the former, hydrogen bonding of water is hindered yet persists near the solutes. In the latter, hydrogen bonding is depleted, leading to drying of extended apolar surfaces, large forces of attraction, and hysteresis on mesoscopic length scales. The crossover occurs on nanometer length scales, when the local concentration of apolar units is sufficiently high, or when an apolar surface is sufficiently large. Our theory for the crossover has implications concerning the stability of protein assemblies and protein folding.

We perform Glauber dynamics Monte Carlo simulations of a lattice gas confined between drying walls to model the dynamics that leads to the evaporation of water between extended hydrophobic surfaces. We find direct evidence that the long and short wavelength fluctuations are the important features involved in the evaporation process. These fluctuations correspond to capillary wave fluctuations in the emerging liquid-vapor interfaces and to the formation of vapor tubes that bridge across the interfaces.

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