RHEOLOGICAL BEHAVIOR OF WEAKLY AGGREGATING COLLOIDS - VISCOSITY OF THE STRUCTURE FORMED IN A STEADY SHEAR-FLOW

Experimental data on the steady shear viscosity of a weakly aggregatin g dispersion of polystyrene latex are described in terms of a microrhe ological model. This model combines the concept of fractal aggregation with the transient network modeling analogous to that known for polym er dynamics. The calculations are performed with account both for the hydrodynamic interaction of aggregates and for the binding of aggregat es by chains of particles. The theory does not only agree well with ex perimental data, but is also useful for the determination of structura l parameters (fractal dimension, etc).