Curvature effects on hydrophobic solvation

Abstract

Molecular dynamics simulations were performed on four systems: pure SPC/E water, and three solutes with different surface curvatures in water. The same intermolecular potential was employed throughout, but the radius of curvature was altered by inserting a hard 'inner core' into the solute. The radial distribution function, angular distribution, a bond-order parameter, a hydrogen bond analysis and a near-neighbour analysis were used to assess the static properties of water molecules in the first solvation shell and in the bulk phase, while their dynamic behaviour was examined using various velocity and reorientational autocorrelation functions. Water molecules in the solvation shell exhibit enhanced structuring, but this structuring is decreased when the curvature is decreased. The translational and rotational dynamics of water are slowed down, but the effect is independent of curvature.