CONTINUUM ELECTROSTATIC INTERACTIONS BETWEEN PLANAR LATTICES OF DIPOLES AND THE POSSIBLE RELEVANCE TO THE HYDRATION FORCE

The electrostatic interaction between two planar dipolar lattices in dielectric continua is investigated. If there are no dielectric images, the pressure is equally likely to be attractive or repulsive, depending upon the relative lateral displacement of the two lattices. In addition to perfect dipolar lattices, we consider the effects of real dipoles, of disorder, and of finite-sized domains. When the surfaces constitute the boundary between dielectric media, and when there are no correlations between the two surfaces, then there occurs a strong exponentially decaying repulsion due to the interaction between a lattice and its dielectric images. The relevance of this repulsion to the hydration force is discussed, and an experimental test that should discriminate between different theories for that force is proposed.