THE STABILITY RATIO FOR A DISPERSION OF PARTICLES COVERED BY AN ION-PENETRABLE CHARGED MEMBRANE

The electrostatic interaction between two particles covered by an ion- penetrable charged membrane suspended in an a:b electrolyte solution i s estimated. A perturbation method is employed to solve the governing nonlinear Poisson-Boltzmann equation. The approximate analytical expre ssion derived for potential distribution yields a sufficiently accurat e estimate, Both the stability ratio and the critical coagulation conc entration of the counterions of the system under consideration are der ived. The results of a numerical simulation reveal that the stability ratio decreases with an increase in the size of a particle and increas es with the total amount of fixed charges in the membrane phase. For a constant total amount of fixed charges and particle size, the stabili ty ratio increases with a decrease in the thickness of the membrane. W e show that monodispersed particles are more stable than polydispersed particles. (C) 1996 Academic Press, Inc.