engleski

Growth of silver iodide particles investigated by light scattering

The kinetics of growth and aggregation of polydispersed colloidal silver iodide particles was followed by static and dynamic light scattering. From the diffusion coefficients the hydrodynamic diameters and particle size distribution were determined. Polydispersity of silver iodide colloids was confirmed by dynamic light scattering, showing bimodal and trimodal particle size distribution. The model of the formation of solid phase from homogeneous solution was established, considering these processes as consecutive ones. Since the particle sizes are kinetic dependent, they were normalized under the conditions of chosen concentration of colloid and the time passed from its preparation. The result of the normalization of spatial and temporal extents showed that the particle sizes estimated by the normalized conditions within a big scale of the concentration gradient and the related time of measurement, showed the same values within the precision limits ; the average hydrodynamic diameter of aggregates amounted to <dh > = (68.3ą8.0) nm. It was shown that using such an interpretation the low polydispersity of samples was found. It also means that normalizing the size of polydispersed colloidal aggregates enables the treatment of the polydispersed colloid as the monodispersed one under the defined condition. Furthermore, such an approach showed that the colloidal aggregation can be kinetically treated as a development of a fractalized process, i.e., the process that refers to the step-wise aggregation which can be considered kinetically self-similar.

Kinetics of aggregation; Light scattering; Polydispersed colloid

nije evidentirano