The role of gold nanoparticles in the structural and electrical properties of Cs/PVP blend

Pure gold nanoparticles (AuNPs) were prepared using a laser ablation technique. Nanocomposite films of chitosan (Cs) and polyvinyl pyrrolidone PVP blend embedded different concentrations of pure gold nanoparticles were prepared by the casting method. The structural, morphological, thermal and electrical properties of Cs/PVP-AuNPs nanocomposite were characterized and investigated before and after adding gold nanoparticles. The X-ray diffraction revealed the degree of crystallinity of Cs/PVP blend was decreased after the addition of gold nanoparticles. The intensity of some IR bands was changed due to the chemical interaction between the blend and AuNPs. Transmission electron microscope images of the samples which contain the gold nanoparticles show the spherical particles of nanogold with a size range nearly 5-30 nm. The thermogravimetric (TG) analysis shows an enhancement of the thermal stability of the films after the addition of AuNPs. The activation energy was calculated from the TG curves using Coats-Redfern and Broido methods. The AC electrical properties were studied from 100 Hz to 5 MHz with different temperatures. The values for dielectric constant (epsilon ') and dielectric loss (epsilon '') were decreased with an increase in both frequency and temperature.