Influence of titanium chloride addition on the optical and dielectric properties of PVA films

Polymeric films based on polyvinyl alcohol (PVA) doped with titanium chloride (TiCl3) at different weight percent ratios were prepared using the solvent cast technique. The structural properties of these polymeric films are examined by XRD and FTIR studies. The complexation of the clopant with the polymer was confirmed by FTIR studies. The XRD pattern reveals that the amorphous domains of PVA polymer matrix increased with raising the TiCl3 content. The optical properties of these polymeric films were examined by optical absorption and emission spectroscopy. Electrical conductivity was measured at room temperature of pure PVA and PVA doped with different concentrations of TiCl3 from 20 Hz to 3 MHz. The conductivity was found to increase with the increase in clopant concentration. The dielectric constant (epsilon') indicates a strong dielectric dispersion in the studied frequency range and increases as clopant content increases. This increase in both sigma and epsilon' is attributed to the increase in the localized charges distribution. Moreover, a loss peak was identified in the dielectric loss spectra and it is attributed to the orientation of polar groups. (C) 2009 Elsevier B.V. All rights reserved.