Model of synthesis of ZnS nanoparticles stabilized by cetyltrimethylammonium bromide

摘要

A mathematical model of synthesis and stabilization of ZnS nanoparticles in aqueoussolutions of cetyltrimethylammonium bromide (CTAB) is presented. ZnS nanoparticlesprecipitated by the reaction of sodium sulphide and zinc acetate are significantlyinfluenced by CTAB both in a stage of nucleation and in a stage of growth andstabilization. The suggested model assumes a dominating influence of the nucleation stageon future properties of emerging ZnS nanoparticles. On the basis of a calculated nucleationrate depending on a degree of the ZnS supersaturation, the model adopts an approximateassumption that ZnS nuclei are formed all at one moment.Mathematical formulation of thenucleation model attempts to explain a recently observed relationship between ZnSnanoparticles radii and the CTAB concentration. The dependence of a surface tension ofzinc acetate and CTAB aqueous solutions on the CTAB concentration was measured andfurther applied to obtain the relation between the CTAB monomer concentration and theCTAB total concentration. The nucleation model assumed a key role of CTAB monomers,which were considered as nucleation centres. The predicted radii