Measuring the fractal dimension of colloidal aggregates

Progress in Science depends more and more on the interplay between different disciplines like Physics, Mathematics, Chemistry, etc., This becomes very obvious for the study of colloidal aggregation. In this article we show how the use of the Fractal Dimension concept, together with light scattering theory, allows to advance substantially in the understanding of these structure formation processes. As a first step, we discuss why a colloidal aggregate may be considered as fractal. Then, we show how light scattering can reveal the fractal nature of colloidal aggregates. Finally, we present experimental results that confirm the previous ideas using small spherical particles. We obtain the Fractal Dimensions of aggregates formed by polystyrene particles of 40, 184 and 240 nm in diameter, respectively when its aggregation is induced by salt. The article is directed to stimulate the interest in Colloidal Physics. (Author) 13 refs