Statistical Mechanical Theory of Double-Layer Structure and Properties

Publisher Website
Google Scholar
Abstract
The general cluster theory of inhomogeneous fluids is applied to the determination of ion and mean potential distributions in the interfacial region between electrolytic solutions and metallic electrodes (specifically mercury), as well as in colloidal suspensions. The relevant electrostatic problem involving distinct inner and outer Helmholtz regions is solved in closed form. Summation of the linearized cyclic clusters appropriate to dilute solutions demonstrates for the first time the limitations of local Debye—Hückel activity corrections in the method called ``local thermodynamic balance.'' An explicit adsorption isotherm formalism results from proper treatment of cluster vertices confined to the inner Helmholtz plane; this permits proper deduction of the ``discreteness‐of‐charge'' effect, as well as nonelectrostatic ion size effects in this plane. It is furthermore shown that accounting for ion size to lowest order in the diffuse layer necessarily contradicts the local thermodynamic balance approach. The systematic cluster theory formulation of the colloid stability problem also suggests hitherto unused corrections to the relevant double‐layer free energies.

This publication has 19 references indexed in Scilit: