Fabrication of anatase and rutile TiO ₂ phases: electrical properties of thermoplastic nanocomposite membranes

TiO 2 nanoparticles were synthesized by a sol–gel method and calcined at 400 °C and 700 °C to obtain anatase and rutile powders, respectively. The aim of this work was to investigate the effect of TiO 2 crystalline phase and filler loading on the dielectric and electrical properties of PVA–PEG–PVP nanocomposite membranes. Polymer nanocomposites were prepared by incorporating TiO 2 (5–25 wt%) into a PVA–PEG–PVP blend containing 10 wt% PEG and 5 wt% PVP. Dielectric and electrical properties were studied over 10 2 –10 6 Hz at room temperature, while DC transport was examined between 293.15 and 378.15 K. The dielectric constant decreased with increasing frequency. At 1 MHz and 25 wt% TiO 2 , ε′ increased from 6.43 for anatase to 8.57 for rutile, while dielectric loss decreased from 0.061 to 0.046. The highest AC conductivity was observed at 20 wt% TiO 2 , reaching 1.0 × 10 −4 and 8.6 × 10 −5 S m −1 for the 400 and 700 °C series, respectively. DC conductivity increased with temperature, and activation energy decreased from 0.65 eV for the polymer blend to 0.128–0.087 eV at 25 wt% TiO 2 . These results highlight the potential of the prepared membranes for dielectric and electrical insulation applications.