Effect of Polyvinyl Pyrrolidone Molecular Weight on the Silver Morphology Synthesized by N, N-Dimethylformamide Reduction

Abstract

Nanosized silver (Ag) was synthesized by reducing high concentration AgNO3 in N, N-dimethylformamide (DMF), in the presence of stabilizer polyvinyl pyrrolidone (PVP). PVP of two different molecular weights (MW=40000, 1300000) at the reaction temperature of 80°C and 100°C were tested for the effect on the formation of diverse silver nanoparticles. Our results indicated that the PVP with different molecular weights plays different role in the controlling of the Ag nanostructure owing to the PVP molecular selective adsorption on different crystal facets, thus affecting the growth rate of different facets of Ag nanoparticles. When all the other conditions kept the same and the temperature of 100°C, if PVP (Mw=40,000) was used, only a small amount of Ag decahedra were found. However, when the PVP with larger molecular weight such as PVP K88 (Mw=1300, 000), a large quantity of the triangular nanoprisms existed in the final solution in spite of the minority of quasi-sphere. The growth process and causation of different silver morphology with two distinct PVP have been briefly discussed.