DIELECTRIC-DISPERSION OF DILUTE SUSPENSIONS OF COLLOID PARTICLES - PRACTICAL APPLICATIONS

The two characteristic relaxation frequencies at which either the Maxw ell-Wagner or the double layer polarization mechanism prevails have be en defined in terms of characteristic parameters for colloidal suspens ions subjected to an oscillating electric field. Both frequencies are found to increase with increasing ion diffusion coefficient, with decr easing particle radius, and with increasing salinity. For both thin an d thick double layers, these frequencies appear to be invariant at low zeta potential (zeta) values. Correlations are developed between thes e characteristic relaxation frequencies and the colloid suspension par ameters. The correlations constants appear to be related to the Boltzm an constant, temperature, and electrostatic charge. These correlations can be useful for estimating particle size and counterion diffusion c oefficient and can be used in developing dielectric dispersion models for colloid particles suspensions and for porous media. A rigorous dis persion model has been inverted to reciprocate simultaneously the aver age zeta potential (zeta), particle size, and particle volume fraction of the dispersed material from dielectric permittivity data at three distinct frequencies, Relaxation of colloidal suspensions appears to b e an adequate alternative for quantifying these parameters as opposed to using intricate measurements of electrophoretic mobility.