Low-frequency dielectric dispersion in colloidal suspensions of uncharged insulating particles

The standard electrokinetic equations for a spherical uncharged insulating particle suspended in a binary electrolyte solution with an applied ac electric field are analytically solved in the general case when both the ion diffusion coefficients and valences have arbitrary values. It is shown that under these conditions, the field-induced ion density profiles extend at low frequencies at far larger distances from the particle than in the case when both diffusion coefficients have the same value. The corresponding induced charge density modifies the dipolar coefficient, leading to an additional low-frequency dielectric dispersion.