Simultaneous measurements of small-angle static and dynamic light scattering to characterize particle aggregation

We propose a simple optical instrument that simultaneously measures small-angle static and dynamic light scattering from video images, providing on-site characterization of particle aggregation. The system achieves low-frame-rate photographic measurements by integrating a collimating lens for forward light scattering with a complementary metal-oxide-semiconductor image sensor. Image analysis yields both a structural index parameter of a fractal dimension and a kinetic index of a diffusion coefficient, supporting real-time evaluation of aggregation dynamics. Using polystyrene latex particles, we demonstrate that the method reliably captures electrolyte-induced aggregation, highlighting its potential for process monitoring.