Self-Focusing Dynamics in Monopolarly Charged Suspensions

The Smoluchowski equation for irreversible aggregation in suspensions of equally charged particles is studied. Accumulation of charges during the aggregation process leads to a crossover from power-law to sublogarithmic cluster growth at a characteristic time and cluster size. For larger times the suspension is usually called stable, although aggregation still proceeds slowly. In this regime the size distribution evolves towards a universal scaling form, independent of any parameter included in the theory. The relative width falls off to a universal value σ_r^∞≈0.2017 that is much smaller than in the uncharged case. We conjecture that σ_r^∞ is a lower bound for the asymptotic relative width for all physical systems with irreversible aggregation.