V. Aguilella et al., A PERTURBED ELECTRIC DOUBLE-LAYER NEAR A SOFT POLAR INTERFACE, Journal of colloid and interface science, 186(1), 1997, pp. 212-214
A perturbation analysis is applied to a nonequilibrium double electric
layer (NDEL) near a membrane with extended soft permeable interfaces
(polar zones) under steady-state ion flux conditions. The membrane has
been modeled as composed of three layers: an inner hydrophobic layer
and two polar zones with fixed charges and dipoles. Ion flux is descri
bed according to Nernst-Planck and Poisson equations, A first order ap
proximation of the nonequilibrium electric potential has been obtained
, using the electric current as the small parameter. The influence of
the ionic flux, the surface dipole density, and the thickness of the p
olar zone on the NDEL near the membrane has been analyzed. The electri
c potential and hence the ion concentration profiles in the NDEL chang
e considerably with surface dipole density. A maximum in the electric
potential, which is determined by ion flux and polar zone parameters,
is predicted in certain cases. The effects shown can help in the inter
pretation of permselectivity measurements. (C) 1997 Academic Press