Water at Hydrophobic Substrates:Curvature,Pressure,and Temperature Effects

摘要

We studied the water density profile close to spherical and planar hydrophobic objects using molecular dynamics (MD) simulations.For normál pressure and room temperature,the depletion layer thickness of a planar substráte is ~2.5 á.Even for quite large spherical solutes with a rádius of R = 18 A,the depletion layer thickness is reduced by 30%,which shows that substráte curvature and roughness is an experimentally important factor.Rising temperature leads to a substantial increase of the depletion layer thickness.The compressibility of the depletion layer is found to be surprisingly smáli and only -5 times higher than that of bulk water.A high electrostatic surface potential of 0.5 V is found,which presumably plays an important role in the presence of charged solutes,since it can promote adsorption into the interfacial layer.