Effect of chain length of oxyethylene group on particle size and absorption spectra of silver nanoparticles prepared in non-ionic water-in-oil microemulsions

The formation of silver nanoparticles by the method of reduction of silver ions by sodium borohydride in non-ionic water-in-oil microemulsion was inve stigated as a function of structure of the surfactant. Three types of non-i onic surfactants were selected differing in the chain length of the oxyethy lene groups for example: NP-5. NP-9 and NP-II. The silver nanoparticles wer e characterized by UV-Visible Absorption Spectroscopy and Transmission Elec tron Microscopy, TEM. The results of this study showed that the particle si ze is relatively smaller incase of NP-9 while for NP-5 and NP-II the sizes are comparable. This observation is explained on the basis of structure of the droplets and the influence of intermicellar exchange on nucleation and growth of particles.