Microwave Synthesis of Oleylamine-capped Ag Nanoparticles in Aqueous Solution

Ag nanoparticles have been synthesized using microwave irradiation. Oleylamine (OA) was used as stabilizer and capping agent, dimethylformamide (DMF) as reducing agent and deionized water as solvent. UV-Vis spectroscopy was used for the observation of absorbance peak as a sign of nanoparticle formation and size distribution. The synthetic parameters: OA/Ag, DMF, Ag concentration and the microwave irradiation power and time were optimized systematically. It was found that with the increase of OA/Ag mole ratio up to 100, the size of nanoparticles decreases up to 10 nm. The excess of OA in the solution plays a disturbing role in covering Ag nanoparticles and causes agglomeration and growth of nanoparticles. Optimized mole ratio of OA/Ag is accompanied with the use of 0.05 ml of DMF at 540 W microwave irradiation power for 30 sec. Transmission electron microscopy was employed to give clear evidence of nanoparticle formation with the sizes range from 10 nm - 20 nm. Fourier Transformed Infra-Red spectroscopy demonstrated that the particles have been capped successfully with OA in aqueous solution. The capped nanoparticles are polar and can be used in biological applications and also for the deposition of metal-oxide shells on their surface.