EFFECT OF VISCOSITY ON PARTICLE GENERATION IN LIQUID-PHASE

The engineering model, where the number concentration of particles gen erated by homogeneous nucleation n is determined so that the generati on rate of monomers G is equal to their vanishing rate at monomer con centration C, which corresponds to a critical supersaturated state of nucleation, has been proposed by the present authors (Kousaka and Nom ura, Kagaku Kogaku Ronbunsyu, 23, 666-672 (1997)), The cell model, whi ch is familiar in particle dispersed systems, is applied and the solut ion of unsteady diffusion rate of monomers onto a nucleus is used in t he analysis. As a result, we obtain the relation among the parameters as G = 4 pi r*DC*n*, where D is diffusion coefficient of monomer, and r is radius of nucleus. The effect of monomer diffusion coefficient on particle generation, which is one of the factors included in the en gineering model, is studied for systems where silver particles are gen erated by a reduction method in the liquid phase. The monomer diffusio n coefficient is controlled by changing viscosity of the solution by a ddition of a thickener, and it is found experimentally that the number concentration of particles generated is inversely proportional to the monomer diffusion coefficient resulting in particle size reduction, w hich quantitatively support the model.