DC conductivity studies of doped polyaniline tungsten oxide nanocomposites

Abstract

Camphor sulfonic acid (CSA) doped polyaniline (PANI) and tungsten oxide (WO₃) composites (PANI/CSA/WO₃) have been prepared by <i>in situ</i> deposition technique by placing different wt% of fine grade nano powder of WO₃(PANI/CSA/WO­₃ -10, -20, -30, -40 and -50%) during polymerization of polyaniline. The polymerization of aniline is carried by using ammonium peroxydisulfate as oxidizing agent. The composites are characterized by various physical methods such as Fourier transform infrared spectra (FTIR), X-ray diffractogram (XRD), thermo-gravimetric analysis (TGA), scanning electron micrograph (SEM) and transmission electron micrographs (TEM). The FTIR spectral data shows the homogeneous distribution of WO₃ nano particles in PANI/CSA polymer matrix. The TGA reveals that PANI interacted strongly with the WO₃-SO₃H, enhancing the thermal stability of polyaniline. The SEM images indicate that increase of WO₃ wt% in PANI/CSA/WO₃ composites, enhances the compactness of the matrix. The TEM image clearly shows the size distribution of WO₃ nanoparticles formed during the reaction and ranges from 150 to 200 nm. The temperature dependent DC conductivity of PANI/CSA/WO₃ composites is studied in the temperature range 308-433 K. The results of PANI/CSA/WO₃ indicate strong interaction of PANI/CSA with WO₃ in the composites. The study of DC conductivity shows an evidence for the transport properties of the composites. Due to the positive temperature coefficient of resistance of WO₃, these composites can signify in development of new materials in temperature dependent applications.