Size Control of Gold Nanoparticles Synthesized by Poly(vinyl pyrrolidone) Reduction in Microwave Synthesis

S.K. Seol, D. Kim, S. Jung, W.S. Chang, Y.M. Bae, Y. Hwu
KERI(Korea Electrotechnology Research Institute), KR

Keywords: PVP stabilized gold nanoparticle, PVP reduction, size control, MW synthesis

Summary:

The properties of gold nanoparticles (AuNPs) depend strongly on their characteristics such as shape, size and size distribution. Therefore the key issue in AuNPs synthesis is to synthesize small sized nanoparticles with uniform size distribution. Here, PVP (poly(vinyl pyrrolidone)) stabilized gold nanoparticles (PVP-AuNPs) are synthesized in aqueous solution contained PVP as reducing and stabilizing agents by microwave heating of 1minute. The size and uniformity of PVP-AuNPs are changed by adjusting concentration of sodium citrate (Na3Ct). The dominant role of Na3Ct in this process is to decrease the reduction rate of gold chloride ions. Due to the increase of Na3Ct concentration, the decrease of the amount of PVP adsorbed on the growing surface of primary AuNPs and the formation of less reactive gold solute complexes lead to stable reactions, resulting in size decrease and uniformity improvement of synthesized PVP-AuNPs. We therefore demonstrate that by adjusting the Na3Ct concentration in microwave synthesis, the diameter of PVP-AuNPs is modulated from 19.47±3.97nm to 7.94±0.14nm at same concentration of chloroauric acid (HAuCl4) and PVP.