Thin double layer approximation for electrophoresis and dielectric response

Abstract

An earlier thin double layer approximation for the dielectric response of spherical macroions is extended to allow calculation of the electrophoretic mobility and inclusion of convective polarization of the ion atmosphere. Comparison is made with exact numerical results and with other thin double layer approximations. The approximation gives fairly accurate values of the dielectric response at macroion radii down to 50 D lengths, for the range of zeta potentials 0≤ζR≤8, where ζR is the reduced zeta potential and D is the Debye length. The accuracy worsens gradually with decreasing size and increasing zeta potential. Electrophoretic mobility results are considerably better.