Electrical conductivity and dielectric characteristics of in situ prepared PVA/HgS nanocomposite films

Polyvinyl alcohol (PVA) and mercury sulfide (HgS) polymer nanocomposite were prepared using the solution casting and the in situ chemical reduction of mercury nitrate (Hg(NO₃)₂) and sodium sulfide (Na₂S) in aqueous solutions of PVA as capping for different molar content of Hg(NO₃)₂ and Na₂S. The nanocomposites films were characterized by Fourier transform infrared, X-ray diffraction (XRD), and scanning electron microscopy. The XRD results for the nanoparticles revealed the hexagonal structure of the HgS, (α-phase). The influence of embedded HgS nanoparticles on the conductivity and dielectric properties of PVA films are investigated, over the frequency range 1 kHz–1 MHz, and the temperature range 30–110 °C. The variation of ac-conductivity with a frequency of the films follows Jonscher’s universal power law and found to be increased with increasing temperature, frequency and nanoparticle content. The variation of frequency exponent (s) indicated that the conduction mechanism was correlated barrier hopping model. The dielectric constant (ɛ′), and dielectric loss (ɛ″) was found to decrease with increasing frequency, but increase with increasing temperature and HgS nanoparticles content. The dc-conductivity (σ _dc ) increase with increase of HgS concentration, and follows Arrhenius behavior in the investigated temperature region.