Analysis and prediction of cluster formation

An experimental and theoretical analysis of the interaction of titanium dioxide particles during coagulation was performed, using laser light dynamic scattering (LDS) and both von Smoluchowski and reversible coagulation approaches. For cluster formation, different initial particle numbers and different shear rates were investigated and the experimental data were fitted to a mathematical model based on aggregation and disaggregation processes. The primary particle size was less than 1 micrometre, but in all cases the LDS information showed that primary clusters of 3.5 micrometres were rapidly formed, which then went on to cluster further to provide larger aggregates. Hence, the modelling approach was one of cluster-cluster aggregation and disaggregation, rather than primary particle aggregation.