Aggregation in interfacial colloidal systems

Abstract

The structure and growth dynamics of two dimensional aggregation of 1 µm polystyrene latex particles trapped at the air-water interface have been observed. For some time after induction of growth rather compact clusters grew slowly; thereafter the clusters became much more mobile and rapidly aggregated into more ramified structures. The clusters were fractal, the R ²_g -N plot plot yielding a Hausdorf dimension of 1.46 ± 0.02, typical of diffusion limited cluster aggregation. The growth dynamics displayed scaling appropriate to this model. The dynamic scaling exponents were rather imprecisely determined, but did satisfy the scaling relation proposed for cluster-cluster aggregation. The observed static scaling exponent of the size distribution function and the crossover of cluster statistics were in excellent agreement with expectation.