LIGHT-SCATTERING STUDY ON THE FRACTAL AGGREGATES OF POLYSTYRENE SPHERES - KINETIC AND STRUCTURAL APPROACHES

Static and dynamic light-scattering measurements on the fractal aggregates of polystyrene spheres (diameter=40 nm), induced by the addition of salt (0.2-1.5 mol·dm-3NaCl) at a constant pH of 9.2, are presented. The kinetic approach with the use of dynamic light scattering enables us to distinguish between fast and slow aggregation and the structural approach by using static light scattering provides us an appropriate way to determine the fractal dimension. By using the DLVO colloid stability theory to calculate the potential energy curves between polystyrene spheres at various salt concentrations we have concluded that the interparticle interactions would not only govern the kinetic growth of clusters, but also determine the fractal structure and the degree of cluster restructuring. In the category of fast aggregation, the smaller the interparticle attraction in the primary minimum, the larger the fractal dimension resulted from restructuring. © 1991.