Synthesis of Sorbitan Ester Stabilized Uniform Spherical Silver Nanoparticles

Controllable synthesis of uniform spherical silver nanoparticles was investigated by carrying out a chemical reduction reaction in a micro emulsion, formed under high shear mixing of aqueous silver nitrate solution and 2-ethyl hexanol as organic phase. Sodium borohydride was used as reducing agent and sorbitan monooleate (span-80) as stabilizer. Further, a study has been performed to observe the effect of silver nitrate concentration, reducing agent concentration, amount of surfactant and organic phase on the size and shape of silver nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques were used for elucidating the shape, size and size distribution of the synthesized silver nanoparticles. Crystal structure of silver nanoparticles thus prepared has been studied by X-ray diffraction analysis (XRD). Uniform silver nanoparticles of average diameter 15-20 nm with high purity and well crystalline nature were obtained under optimized set of conditions. The results of synthesis of these nanoparticles in present study were excellent and may also be used at larger scale.