Preparation And Characterization Of Silver Nanop Articles

Silver nanoparticles is easy to aggregate owing to the smaller size, the higher surfacearea and surface activity, which limit its stability and applications in optical and electricfields. By adding surfactant and the choice of the reaction systems have become a keytechnology in order to prevent aggregation for the synthesized silver nanoparticles.In this paper, different morphologies and crystalline properties of silver nanoparticleshave been synthesized by using silver nitrate as precursor, sodium oleate and KH-550(3-aminopropyl-triethoxysilyl) as surfactants, DMF (N, N-dimethylformamide)、ethyleneglycol、ethanol as the reducing agents and solvents, and by changing the reactionconditions in chemical reduction method. The effects of different reaction conditions onsilver nanoparticles have been investigated systematically through UV-visiblespectrophotometer, transmission electron microscopy and X-ray diffraction.Silver nanoparticles have been synthesized by using sodium oleate as surfactant,water (DMF as raductant)、ethylene glycol、ethanol as solvent. In water system, it has beenfound that silver hydrosol could be prepared by changing the reaction time, the reactiontemperature, the amounts of reductant; the above factors on the kinetic of silvernanoparticles formaiton are studied, and it is obviously found that the optical properties,size and morphology of the silver nanoparticles could be affected by reaction temperatureand reductant. In ethylene glycol and ethanol systems, a floc silver nanoparticles can besynthesized by changing the reaction conditions; the influence of the reaction time,reaction temperature, and reactant ratio on the optical properties, size and morphology ofthe silver nanoparticles have been studied; the state of the formation of silver nanoparticlesprepared in ethylene glycol systems changes from floc to emulsion with the decrease ofreactant concentration, and this critical concentration is about2×10-3mol/L, but there is nosuch a transformation taking place in ethanol system.Silver nanoparticles have been synthesized by using KH-550as surfactant, DMF asraductant. It has been suggested that KH-550played a good modification on the surface ofsilver nanoparticles, with the reaction temperature and time go up, the reaction rate rises; the molal ratio of KH-550with silver nitrate and concentration of the reactants could effectheavily on the growth process of silver nanoparticles; the transformation of morphologyfrom spherical to non-spherical could be clearly observed at1min~4h with reactiontemperature60℃.