DLVO theory for like-charged polyelectrolyte and surface interactions

The mechanism of adsorption of charged polymers onto like-charged surfaces has been a matter of debates in recent years. We propose a mean-field theory for the interactions of like-charged polyelectrolyte and a plane surface in the presence of 1:1 and 2:1 electrolyte, which takes into account long-range van der Waals and double-layer forces. The theory is able to predict the optimum conditions, such as solvent composition, pH and temperature, for polyelectrolyte adsorption on like-charged surfaces as well as to account for the conformational properties of a polymer at the surfaces. An excellent agreement of the predictions of the theory with the available experimental data suggests that it can be used as a simple tool for predicting the optimum conditions for studying various polyelectrolyte properties, including their biological activity, at the surfaces. Particularly simple expressions for the polymer/surface interaction energy have been obtained in the Debye–Huckel limit. The applicability of this approximation to the biological molecules at the surfaces is discussed.