COARSENING PHENOMENON IN 2-DIMENSIONAL COLLOIDAL AGGREGATION AND CRYSTALLIZATION

Late stage coarsening (Ostwald ripening) phenomenon in a two-dimension al colloidal system has been investigated via in situ observation of c lusters in a polystyrene colloidal firm subjected to an external alter nating electric field. In a regime with a growth exponent n approximat e to 0.23 for the mean cluster gyration radius (r(g)), the gyration ra dius distribution broadens with time and scales as r(g)(df)F(r(g)/[r(g )]), the exponent is the fractal dimension of the aggregation system.