Sol-Gel transition in dense dispersions: Effect of particle bridging

Abstract

Sol-gel transition in dense dispersions of particles is modeled through the use of statistical mechanical and continuum percolation theories. Specifically, we examine the effect of particle bridging on the gelation and clustering of a binary dispersion of particles which interact through a short-ranged potential represented by the adhesive hard-sphere model. The gelation thresholds for dense dispersions are determined analytically as a function of the particle concentrations, particle size ratios, and interparticle interaction within the context of the Percus-Yevick integral equation theory. It is found that depending on the temperature, particle concentration, and particle size ratio, the dispersion may undergo a single sol-to-gel transition, or a series of sol-to-gel, gel-to-sol, and sol-to-gel transitions. Pair-connectedness functions which account for the degree of aggregation in the dispersion are also determined analytically in the Percus-Yevick approximation.