Stability, size and optical properties of colloidal silver nanoparticles prepared by electrical arc discharge in water

We have fabricated and characterised colloidal silver nanoparticles by the electrical arc discharge method in DI water. Size and optical properties of the silver nanoparticles were studied versus different arc currents. Optical absorption indicates a plasmonic peak at 392 nm for 10 A which increases to 398 nm for 20 A arc current. This reveals that by raising the arc current the size of the nanoparticles increases. Optical absorption of silver nanoparticles after 3 weeks shows precipitation of them in a water medium. The effect of different surfactant and stabilizer concentrations such as cethyl trimethylammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), sodium citrate, sodium dodecyl sulfate (SDS), sodium di-2-ethylsulfosuccinate (AOT) and carboxymethyl cellulose (CMC) on the stability of silver nanoparticles was investigated. The colloidal silver nanoparticles with 100 mu M concentration were stable for more than 3 months at 50 mu M CTAB and 6 months at 10 mu M sodium citrate concentration, respectively. SEM images of the sample prepared at 50 mu M CTAB concentration reveal uniform and fine nanoparticles. The mean size from TEM images is about 14 nm. TEM images of the sample prepared at 10 mu M sodium citrate concentration show a shell of citrate that covers the silver nanoparticles.