A STUDY OF KINETICS OF POLYSTYRENE AGGREGATION PROGRESS USING DYNAMICLIGHT-SCATTERING

On the basis of dynamic light scattering, the kinetics of the aggregat ion process in salt-induced water solutions of polystyrene latex parti cles is investigated for various ionic strength (0.1 less than or equa l to mu less than or equal to 2.5). Our results show that aggregation of clusters can take place either slowly or rapidly, depending on the ionic strength. The rapid process can produce clusters with the fracta l dimensions d = 1.79 +/- 0.02 for 2.0 less than or equal to mu less t han or equal to 2.5 and d = 1.75 +/- 0.02 or 2.09 +/- 0.5 for 0.4 less than or equal to mu less than or equal to 1.5. Clusters with d = 1.75 are always observed to restructure so as to yield d 2.09 +/- 0.05. Th e slow process yields clusters for 0.1 less than or equal to mu less t han or equal to 0.15. It is also shown that the results when electroly tes such as KCl, MgCl2, and CaCl2 are used as flocculating agent are t he same as those for NaCl.