CONTINUUM PERCOLATION AND DEPLETION FLOCCULATION

Using Brownian dynamics simulations, we investigate continuum percolat ion in a system of colloid particles aggregating due to depletion floc culation. For all values of aggregating potential, there is a lower th reshold volume fraction of colloid particles at which a percolating cl uster appears. This threshold defines a percolation ''phase'' boundary that crosses the phase boundary between the colloid fluid phase and c olloid fluid+crystal coexistence. In the two-phase coexistence regime, the lifetime of percolated clusters increases dramatically, and there fore the percolation threshold may be related to a transient gel thres hold reported from experiment. In the phase coexistence regime, there is, evidence of aging due to the thermal restructuring of clusters, im plying a finite lifetime for percolating structures. (C) 1998 American Institute of Physics.