The effects of attractive and repulsive interaction on two-dimensional reaction-limited aggregation

Abstract

The effects of both attractive and repulsive interactions on reaction-limited cluster–cluster aggregation have been explored using a two-dimensional polydisperse off-lattice model. Interactions with a magnitude on the order of kBT(kB is the Boltzmann constant and T is temperature) have an important effect in both the aggregate structure and the kinetics of aggregation. Attractive interactions lead to more compact structures and repulsive interactions lead to less compact structures with a lower effective dimensionality. The effects of power law particle–particle interactions with interaction energies of the form E=A/r Ε (r is distance) on aggregate structure, aggregation kinetics and the evolution of the cluster size distribution were explored for Ε=2, 4, and 6. A mean field variational theory indicates that fractal dimensionality is unchanged if Ε≥2D0 (where D0 is the fractal dimensionality in the absence of interactions) and that D=D0 (Ε+2)/2(D0+1) for Ε in the range 1≤Ε≤2D0. The simulation results are in accord with this theoretical analysis.