THE RAPID AGGREGATION OF DILUTE SUSPENSIONS - AN EXPERIMENTAL INVESTIGATION OF SMOLUCHOWSKI THEOREM USING PHOTON-CORRELATION SPECTROSCOPY

A series of rapidly aggregating hydrophobic suspensions (poly(styrene), AgI and TiO2) were monitored using photon correlation spectroscopy (PCS) employing a theory developed for polymer chains. Deviations from Smoluchowski kinetics are seen in the early stages of the aggregation, although in many cases a limiting value of approximately 6 x 10(-12) cm3 s-1 (close to the diffusion-limited value) is achieved for the coagulation of the larger aggregates. Thus, the data offer an experimental verification of Smoluchowski's theorem and also justify the expressions employed for the hydrodynamic radius and RGD form factors of colloidal aggregates.