Molecular dynamics simulation of water between hydrophobic surfaces. Implication for the long-range hydrophobic force

Molecular dynamics simulations are applied to aqueous media confined between two hydrophobic monolayer surfaces. The oxygen number density of water molecules is shown to be drastically depressed at the monolayer–water interface when the monolayer separation is fully increased (>50 Å). On the basis of this result, we discuss the origin of the so-called `very long-range hydrophobic forceʹ.