Interaction of charged plates which approach at adsorption equilibrium of all specifically adsorbed species

Abstract

An expression is derived which shows how the equilibrium “electrochemical” free energy of interaction of two charged plates in solution can be calculated using classical double layer theory and isotherms for the specific adsorption of the various species present in solution. This expression is independent of any model considerations concerning the inner regions of the double layer. A method for obtaining the necessary adsorption isotherms for specifically adsorbed species from experimental titration data for the potential determining species, which is similarly model independent, is also outlined.