On the kinetics of heteroaggregation versus electrolyte concentration: comparison between simulation and experiment

The heterocoagulation kinetics of two latexes bearing surface charges of op posite sign was studied. The doublet formation kinetic constant was used to determine the evolution of the kinetics. It has been adsorbed a non-ionic surfactant onto the anionic latex in order to increase its stability. Aggre gation experiments were performed for both latexes bared. Also, measurement s were carried out with the anionic latex partially covered. Comparison bet ween these two results showed small differences in the kinetic constant. Th e study of the heteroaggregation kinetic constant versus ionic concentratio n showed a trend opposite to that of the homocoagulation case. The experime ntal results were compared with simulations. The model used for simulations takes into account the interaction forces between particles to perform the random paths for clusters. Comparison showed good agreement. The inclusion of attractive forces was found to be essential for describing processes fa ster than diffusion limited aggregations. (C) 1999 Elsevier Science B.V. Al l rights reserved.