The Hydrophobic Gap at High Hydrostatic Pressures

Abstract

We have gained new insight into the so-called hydrophobic gap,amolecularly thin region of decreased electron density at the interface between water and as olid hydrophobic surface,b yX -rayr eflectivity experiments and molecular dynamics simulations at different hydrostatic pressures.P ressure variations show that the hydrophobic gap persists up to apressure of 5kbar.The electron depletion in the interfacial region strongly decreases with an increase in pressure,i ndicating that the interfacial region is compressed more strongly than bulk water.The decrease is most significant up to 2kbar;b eyond that, the pressure response of the depletion is less pronounced.