Microscopic modelling of absorption of dipoles in electrical double layer

Abstract

(i) A three-state model allowing two orientational states for the solvent and one for the organic adsorbate is analysed to obtain the adsorption isotherm. The approximations under which pseudo Frumkin isotherm can arise are briefly sketched. (ii) Several variations of the model, such as (i) two orientational states for the adsorbate, (ii) the case of α = 0, aₛ = ∞ and (iii) the site-occupancy differences between the solvent and the adsorbate are also briefly indicated. A critique of the earlier theory of Bockris, Devanathan and Muller is discussed in detail and inconsistencies in their formalism are analysed. (iv) Schematic plots of θ vs α at various adsorbate concentrations are given, as a function of molecular parameters.