Limits of the Fractal Dimension for Irreversible Kinetic Aggregation of Gold Colloids

Abstract

We show that there are two regimes of irreversible, kinetic aggregation of aqueous colloids, determined by the short-range interparticle potential, through its control of the sticking probability upon approach of two particles. Each regime has different rate-limiting physics, aggregation dynamics, and cluster-mass distributions, and results in clusters with different fractal dimensions. These results set limits on the fractal dimension, $d_f$, for gold aggregates of $1.75<~d_f<~2.05$ (±0.05).