Influence of Poly(vinylpyrrolidone) concentration on properties of silver nanoparticles manufactured by modified thermal treatment method

Abstract

Very narrow and pure silver nanoparticles were synthesized by modified thermal treatment method via oxygen and nitrogen flow in succession. The structural and optical properties of the calcined silver nanoparticles at 600°C with diverse Poly(vinylpyrrolidone) concentrations varied from 2% to 4% were studied by means of different techniques. Fourier transform infrared spectroscopy was used to monitor the production of pure Ag nanoparticles at a given Poly(vinylpyrrolidone) concentration. The X-ray powder diffraction spectra are evidence for the transformation of the amorphous sample at 30°C to the cubic crystalline nanostructures at the calcination temperatures for all Poly(vinylpyrrolidone) concentrations. The transmission electron microscopy images showed the creation of spherical silver nanoparticles with the average particle size decreased by increasing Poly(vinylpyrrolidone) concentrations from 4.61 nm at 2% to 2.49 nm at 4% Poly(vinylpyrrolidone). The optical properties were investigated by means of UV–vis absorption spectrophotometer, which showed an increase in the conduction band of Ag nanoparticles with increasing Poly(vinylpyrrolidone) concentrations from 2.83 eV at 2% Poly(vinylpyrrolidone) to 2.94 eV at 4% Poly(vinylpyrrolidone) due to decreasing particle size. This was due to less attraction between conduction electrons and metal ions for smaller particle size corresponding to fewer atoms that made up the metal nanoparticles.

Bimetallic Core–Shell Nanoparticles of Gold and Silver via Bioinspired Polydopamine Layer as Surface-Enhanced Raman Spectroscopy (SERS) Platform

“…This observation was furtherly confirmed by the UV-vis absorption spectra, which were given in Figure 8. After the reduction of silver ions, an intense blue shift with remarkably widened spectra was observed for each case of the AuNP@PDOP nanoparticles (see Table 1) [42,43]. The degree of the blue shift is highly correlated with the amount of the reduced silver ions and the resultant silver shell thickness [44][45][46][47][48].…”

Bactericidal and Cytotoxic Properties of Silver Nanoparticles

“…This leads to electrostatic repulsion between AgNPs, thereby preventing agglomeration of nanoparticles [71,75]. Typical polymer-based capping agents are polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and polysaccharides, while non-ionic surfactants including Brij, Tween, and Triton X-100 are employed to stabilize AgNPs during the formation process [76,77]. These stabilizers also play important roles in controlling the size and shape of AgNPs.…”

An Overview of the Synthesis of Gold Nanoparticles Using Radiation Technologies

“…This might occur because higher amounts of polymer in the solution affect the motion of the reduced metal, thus limiting the aggregation of colloids into bigger particles [ 114 ]. PVP was also used as a capping agent for the synthesis of other metallic nanoparticles using thermal treatment [ 115 ]. The same effect can be observed with primary amines during the synthesis of gold nanoparticles, but since these compounds are the reducing and the passivating agents simultaneously, the influence on the particle size is due to the rapid thermal decomposition of the gold-amine complex in water at high temperatures and the subsequent strong protection of the gold nanoparticles by the amines, preventing further aggregation [ 116 ].…”