TOWARD SELF-CONSISTENT CHARACTERIZATIONS OF LOW CONDUCTIVITY DISPERSIONS

The charge per unit mass, the electrophoretic mobility, and the size of particles in low conductivity dispersions can be measured independently. These three characterizations of the dispersed particles are related to each other by a function that depends on the fluid viscosity and particle density. For monodisperse dispersions of insulating spheres this function is (Q/M)d2/m-u = 18-eta/rho-2. Therefore, in low conductivity dispersions three experimental values can be measured independently and checked to see if they are consistent. Such a test is particularly useful for measurements in low conductivity dispersions since these measurements are usually accepted only cautiously. Deviations of measured quantities from this simple relation can also be interpreted as an indication that the dispersion deviates from the assumptions of the simple model, and this is useful information. Several other equivalent functions are derived and all are applied to data taken on various low conductivity dispersions.