Abstract:

Static and dynamic light scattering are major experimental tools to study colloidal aggregates. The theoretical methods for a proper analysis of such experiments are reviewed. It is shown how several interrelated features of the aggregation process determine the experimentally accessible quantities. These features are the structure of the clusters as characterized by their fractal dimension and their anisotropies and the shape of the cluster mass distribution. Using computer-generated clusters, obtained under the conditions of diffusion-limited and of reaction-limited cluster aggregation, and using results for the cluster mass distribution obtained from the Smoluchowski equation for irreversible growth, the static scattering intensity and the correlation function of quasi-elastic light scattering are calculated. The latter is shown to depend sensitively on rotational diffusion processes and on the cluster mass distribution. Finally, it is shown how the growth kinetics can be extracted from the angle dependence of the first cumulant.

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