EFFECTS OF POLAR SOLVENTS ON THE SIZE OF GOLD NANOPARTICLES SYNTHESIZED BY CHEMICAL REDUCTION METHOD

Abstract

In this study, the polarity of the solvent is mentioned as a tool to adjust the size of gold nanoparticles (GNPs) synthesized by chemical method. The influence of the polarization coefficients of the reaction medium on the synthesis of GNPs was investigated. GNPs were synthesized using L-ascorbic acid (L-AA), reducing Au³⁺ ions in the presence of polyvinylpyrrolidone (PVP) surface stabilizer and ethanol solvent. The polarity index of the reaction medium was adjusted by varying the volume ratio of ethanol to water. The results of absorption spectroscopy, dynamic light scattering, and transmission electron microscopy images show that the size of GNPs gradually increases (20 nm - 220 nm) with the decreasing value of the polarization index of the medium (~ 8,0 đến 5,0). Furthermore, the high polarization index of the medium resulted in small size spherical nanoparticles, while the low polarization index of the medium resulted in different shaped GNPs. These results show that the growth and aggregation kinetics of Au atoms strongly depend on the solvent molecules' polarity.