Chapter 13 - Van der Waals Forces between Particles and Surfaces

Abstract

Publisher Summary This chapter presents a study of van der Waals forces between particles and surfaces. van der Waals forces play a central role in all phenomena involving intermolecular forces. While they are not as strong as Coulombic or H-bonding interactions, they are always present and can be important both at small and large separations. van der Waals interaction between macroscopic particles and surfaces is large, even when the bodies are not in contact. In a medium, the interaction strength is reduced by about an order of magnitude and under certain conditions, it can become repulsive. The chapter begins by deriving the van der Waals interaction energies in a vacuum for pairs of bodies of different geometries. The chapter explains the van der Waals force laws for bodies of different geometries. It then discusses the strength of van der Wall forces between bodies in a vacuum or air. The Lifshitz theory of van der Waals forces is presented, and the concept of particle–surface interactions is explained. The nonretarded Hamaker constants are calculated on the basis of the Lifshitz theory. The chapter also explains the concepts of surface and adhesion energies, surface energies of metals, and forces between surfaces with adsorbed layers.