Influence of nonuniform kinetics on particle aggregation

Abstract

Many pathways for the synthesis of novel materials involve aggregation processes that occur in the presence of diffusion barriers and spatially nonuniform kinetics (i.e., the ratio of the timescales of diffusion and reaction depends on the cluster size). In this study, we simulate clusters that grow by diffusion and spatially nonhomogeneous kinetics on two-dimensional square lattices. The influence of nonuniform kinetics on the fractal dimension, particle density distribution, and average diffusion path length is investigated. It is found that if the simulations are performed for a sufficiently long time, the fractal dimension and packing density are not significantly influenced. Specifically, the decrease in the fractal dimension and the increase in the packing density as compared to their values inthe case of diffusion-limited aggregation are relatively small. However, the effective diffusion path length prior to attachment is significantly enhanced, especially for smaller cluster sizes. The implications of these observations for particle aggregation processes are discussed.