Use of two-particle simulations for the evaluation of the flocculation rate in the case of insurmountable repulsive barriers

The interaction potential between two colloidal particles typically spans a few nanometers. Hence the correct appraisal of the potential in simulations requires very short time steps. However, it is often possible to combine one many-particle calculation with several two-particle simulations in order to estimate a set of aggregation rates. As in the theory of Fuchs, this procedure combines the evaluation of the fastest flocculation rate with the calculation of several stability ratios. This methodology was already tested in systems which exhibit low repulsive barriers for primary minimum flocculation. In this article, the procedure is modified in order to calculate an average rate for secondary minimum flocculation. The technique is then used to estimate the influence of drop deformation on the aggregation rate of hexadecane-in-water nano-emulsions stabilized with sodium dodecylsulfate (SDS).