Application of the Cluster-Cluster Aggregation model to an open system

Colloid aggregation is often induced by the change of internal or external conditions. In order to account for the dynamic features of the evolutional open system, a conceptual model for colloid aggregation in open systems was developed based on the classic Cluster-Cluster Aggregation (CCA) model. The extended model allows the important parameters of the classic CCA model, diffusion coefficient D-1 and sticking probability P-1 of primary particles, time-dependent. Consequently, the new model can be used to simulate colloid aggregation in open systems. To demonstrate the applicability of the extended model, the diffusion coefficient D-1 and sticking probability P-1 were defined as a function of solvent evaporation rate and aggregation time in this study. For the simplicity purpose, this study only evaluate D-1(t) while kept P-1(t) as a constant for the simulations. Simulation results indicate that the solvent evaporation altered the aggregation mechanism in various degrees depending on the solvent evaporation rate. This research shows that the extended model based on the classic CCA model is valuable and applicable to open systems. (C) 2009 Elsevier Inc. All rights reserved.