Numerical results for the dielectric dispersion parameters of colloidal suspensions

Numerical spectra for the dielectric relaxation of colloidal suspensions of latex particles in aqueous KCI electrolyte solutions at 25 degreesC were o btained over a wide range of conditions: 10 zeta potential values evenly di stributed between 20 and 200 mV, and 11 kappaa values evenly distributed in logarithmic scale between I and 100. The data were used to determine the p arameter values that characterize both the low- and high-frequency microsco pic (dipolar coefficient) and macroscopic (complex conductivity) dispersion s. The presented results make it possible to directly compare experimental data for suspensions of particles having any size with numerical prediction s, without having to compute the numerical spectra. They also permit us to precisely define the range of applicability of the theoretical expression o f Shilov and Dukhin (Colloid J. 32, 245 (1970)) combined with that of O'Kon ski (J. Phys. Chem. 64, 605 (1960)) for the representation of the dielectri c behavior of colloidal suspensions in a broad frequency range. (C) 2001 Ac ademic Press.