Influence of Fixed Charge Distribution on Ion Mobility: Small Deviations of Equilibrium Potential from Donnan Value

The influence of the electrostatic interaction on the diffusion coefficients of ions is estimated in the approximation of the slightly varying equilibrium potential. Various assumptions have been considered for the fixed charge distribution, namely, the discrete charge distributed in the bulk, the surface charge, and the linear charge distributed around a macroion. Both the random and regular distributions of the fixed charge groups are being separately analyzed as applied to each assumption. Obtained dependencies show in some measure various types of the fixed charge heterogeneity contribute to the effect of the diffusion coefficient decrease. Copyright 1999 Academic Press.