ON THE MICRORHEOLOGICAL MODELING OF AGGREGATING COLLOIDS

Abstract

ABSTRACT Microrheological modeling of the aggregating colloidal dispersions in frames of the mean-field approach Is used to relate their Theological behavior to the parameters of the aggregates. Three parameters are shown to form a minimum set of values which one should know to elaborate the simplest self-consistent microrheological model of aggregating colloids. They are: the yield strength of the compact structure o, fractal dimension D and the exponent m, which characterizes the dependence of the aggregates radius R vs shear rate S (R ∝ S−m). Analytic consideration and computer simulations are carried out to determine the exponent m for the aggregates of different type. The behavior of the aggregate depends on the character of the particles Interaction. In general the interaction force can be considered a superposition of central component (equivalent to ordinary spring) and some non-central component. If the non-central Interaction Is relevant, the aggregate internal structure is rigid (I.e. it elasti...