Numerical Results for the Dielectric Dispersion Parameters of Colloidal Suspensions

Numerical spectra for the dielectric relaxation of colloidal suspensions of latex particles in aqueous KCl electrolyte solutions at 25°C were obtained over a wide range of conditions: 10 ζ potential values evenly distributed between 20 and 200 mV, and 11 κa values evenly distributed in logarithmic scale between 1 and 100. The data were used to determine the parameter values that characterize both the low- and high-frequency microscopic (dipolar coefficient) and macroscopic (complex conductivity) dispersions. The presented results make it possible to directly compare experimental data for suspensions of particles having any size with numerical predictions, without having to compute the numerical spectra. They also permit us to precisely define the range of applicability of the theoretical expression of Shilov and Dukhin (Colloid J.32, 245 (1970)) combined with that of O'Konski (J. Phys. Chem.64, 605 (1960)) for the representation of the dielectric behavior of colloidal suspensions in a broad frequency range.