Studies on Growth Kinetics of Nanoparticles Formation in Bulk Solution

Abstract

Nanoparticles are gaining lots of importance recently due to their exciting applications in different fields like biomedical, pharmaceutical, electronics etc. In this report we studied the mechanism of nucleation and growth of formation of sulfur nanoparticles in aqueous medium. The main objective of this project is to study the effect of various parameters on the growth rate on the basis of size distribution of sulfur nanoparticles. The sulfur nanoparticles were prepared by acid catalyzed precipitation reaction from sodium thiosulphate. The growth rate of the particle depends on various factors, such as reactant concentration, acid to reactant ratio, diffusivity of the sulfur molecules, and temperature of the reaction and surface energy of the particles. As the sulfur nanoparticles are formed by precipitation reaction, the overall process can be divided into nucleation, growth and particle agglomeration. For this reaction nucleation is very fast. Actually as the reaction rate is very fast the growth rate mainly depends on the diffusion of the newborn particle from the bulk phase to the surface of the nuclei. So this is a diffusion limited growth reaction and mainly depends on diffusivity of the particle. The effect of different parameters on the growth rate of the formation of sulfur nanoparticles is studied by using the mathematical model derived by Lifshitz, Slyozov and Wagner and using LSW theory and also the results are compared with the experimental values of the size distribution of the formation of sulfur nanoparticles in aqueous medium.