Patchwise interfacial dipole layers on solids. Application to the silver iodide – aqueous solution interface

Abstract

The hydration of solid particles in aqueous solution is treated as a patchwise phenomenon, in which the orientation of water dipoles varies in a patchwise fashion along the surface. The idea is applied to the AgI system where besides the neutral surface Ag+ patches and I− patches are distinguished. A first-order elaboration is offered, including an analysis of the relation between overall macroscopic quantities and local properties. The model offers an interpretation of two characteristics of double layers on silver iodide: the asymmetry of its p.z.c. and the conspicuous capacitance rise on the positive side and may serve as a starting point for a better description of the typical differences between the double layers on AgI and Hg.