ON THE SELF-CONSISTENT CALCULATIONS OF THE VISCOSITY OF COLLOIDAL DISPERSIONS

Microrheological calculations of the effective shear viscosity of the colloidal dispersions are presented. Two classes of dispersions are considered: stable Brownian dispersions and aggregated disperions. For stable Brownian dispersions hydrodynamic and thermodynamic interactions are considered in terms of the self-consistent approach. According to this approach only two-body interactions are directly taken into account, while many-body interactions are considered in terms of a semiphenomenological analysis, which implies that (in an average sense) each pair of particles interacts via a suspension as a whole rather than through the pure liquid. This analysis makes it possible to calculate the viscosity of a dispersion in a low and high shear rate limit up to the highest volume fraction of particles. For aggregated dispersions an analogous model is applied to the system of aggregates. The aggregates breakup due to the internal stresses in their structure is taken into account. The theoretical calculations are compared with the experimental data. © 1993 Academic Press, Inc.