The effect of shear on colloidal aggregation and gelation studied using small-angle light scattering

In situ light scattering measurements were performed to investigate the effect of low shear rates (0.13-3.56 s(-1)) on an aggregating colloidal system made of 20 nm polystyrene particles. The aggregating system was subjected to a shear for a short period (ca. 33 s) and only once at various times after the onset of aggregation. The effect of shear (aggregation kinetics and morphology) was Studied both in a cluster dilute and in a cluster dense regime (see introduction). Our results have shown that shear can enhance the aggregation and gelation. Shear induced growth can yield hybrid superaggregates when the system is dense. (C) 2008 Elsevier Inc. All rights reserved.