Dynamic scaling and fractal structure of small colloidal clusters

We studied the aggregation of small colloidal polystyrene spheres during the limiting growth regime of diffusion-limited aggregation. The number-average mean cluster size and the fractal dimension of the aggregates were obtained by dynamic and static light scattering (DLS and SLS). The experimental results are interpreted using the spatial and dynamic scaling formalism. The homogeneity exponent λ was used to identify the aggregation mechanism. An unexpected cluster size scaling was observed for early aggregation stages. This feature allowed the use of spatial and dynamic scaling concepts as an alternative method for determining the Smoluchowski rate constant k11.