Non-DLVO, steric and fluctuation forces

The intrinsic nature of hydration force• The hydration force is not of a simple nature It is probably the most important yet the least understood of all theforces in liquids The nature of the surfaces is equally important : ion exchange (addingmore salt or changing the pH for hydrophobic surface, chemicalmodifying for hydrophilic surface)• How do exponentially decaying hydration forces arise? A monotonic exponential repulsion or attraction, possibly superimposedon an oscillatory profile ; simply additive with the monotonic hydrationand DLVO forces with different mechanisms. The short-range hydration force b/n all smooth, rigid or crystallinesurfaces has an oscillatory components.