STUDIES OF RHEOLOGICAL BEHAVIOR OF COLLOIDAL SILICA SUSPENSIONS WITH INTERACTION POTENTIAL

Rheological measurements of both electrostatically and sterically stab ilized silica suspensions are analyzed on the basis of the hard sphere approximation. For electrostatically stabilized suspensions, non-Newt onian viscosity is related to an effective pairwise interaction potent ial. It is shown that the shear rate dependence of viscosity can be pr edicted. For sterically stabilized suspensions, a structural model is used in order to obtain, in particular, low shear viscosity. From its dependence on particle volume fraction, the adsorbed polymer layer thi ckness can be deduced. In addition, the variations of shear modulus as a function of particle volume fraction are scaled with a power law.