Spectroscopic investigations and electrical properties of PVA/PVP blend filled with different concentrations of nickel chloride

Films of PVA/PVP blend (50/50) filled with different concentrations of NiCl2 were prepared by casting method. The prepared films were investigated by different techniques. XRD scans demonstrated that the peak intensity at 2θ≈20° decreased and the band width increased with increase in the concentrations of NiCl2 content, which implied decrease in the degree of crystallization and hence causes increase in the amorphous region. UV–vis analysis revealed that the values of the optical band gap are affected with increase in NiCl2 content. This indicates the formation of charge transfer complexes between the polymer blend and the filler. The rise of conductivity is significant with increased concentration of NiCl2 filler; this reveals an increase in degree of amorphosity. AC conductivity (σac) behavior of all the prepared films was investigated over the frequency range 42 Hz–5 MHz and under different isothermal stabilization in the temperature range 313–393 K. It suggests that the hopping mechanism might be playing an important role in the conduction process in high frequency region. The dielectric behavior was analyzed using dielectric permittivity (ε´, ε″) dielectric loss tangent (tan δ) and electric modulus (M″). The decrease in dielectric permittivity was observed with increase in the concentration of NiCl2 filler. This suggests the role of NiCl2 as filler to improve the electrical conductivity of PVA/PVP blend.

Research Highlights
► Polymeric materials have special interest because, in combination with suitable metal salts, they give complexes that are useful for the development of advanced high energy electrochemical devices, electrochemical display devices, and photo electrochemical cells with ease of fabrication into thin films of desirable sizes.
► NiCl2 is used in polymers for a variety of reasons: cost reduction, improved processing, density control, optical effect, thermal conductivity, control of thermal expansion, electrical properties, magnetic properties, flame retardation, and hardness.