Forward light scattering to characterise structure of flocs composed of large particles

In this work, simulation results were used to test the idea that Fraunhofer diffraction can be used to describe scattering from fractal aggregates. Polystyrene latex of diameter 4.9 μm was aggregated in a forward light scattering instrument, and the fractal dimension was determined independently by the volume obscuration method. Comparison of the experimental data with simulations showed poor agreement. It is suggested that multiple scattering within the aggregate structure, ignored in the usual Fraunhofer formulation, is significant.