ABSTRACT
The percolation behavior of alumina suspensions is studied by computer simulations. The percolation threshold Ïc is calculated, determining the key factors that affect its magnitude: the strength of colloid-colloid attraction and the presence of hydrodynamic interactions (HIs). To isolate the effects of HIs, we compare the results of Brownian Dynamics, which do not include hydrodynamics, with those of Stochastic Rotation Dynamics-Molecular Dynamics, which include hydrodynamics. Our results show that Ïc decreases with the increase of the attraction between the colloids. The inclusion of HIs always leads to more elongated structures during the aggregation process, producing a sizable decrease of Ïc when the colloid-colloid attraction is not too strong. On the other hand, the effects of HIs on Ïc tend to become negligible with increasing attraction strength. Our Ïc values are in good agreement with those estimated by the yield stress model by Flatt and Bowen.