‘‘Confined’’ water and hydrophobic attraction as a result of metastable coordination, stabilized by hydrophobic surfaces

The hydrophobic hydration and interaction between hydrophobic surfaces are treated as a ‘‘wetting phenomenon’’ in terms of a phenomenological Landau–Ginzburg approach. The model is based on the assumption that the breakdown of hydrogen bonds at a hydrophobic wall can stabilize a layer of four-coordinated water near the surface. The theory predicts the formation of more structured, four-coordinated, confined water between two hydrophobic surfaces, when the two layers overlap. A peculiar shape of the disjoining pressure isotherm follows from this picture, including exponential attraction at short and long distances (with longer decay length at short distances), a plateau in between, ended by a jump (first order transition) to the exponential decay at large distances.