This study reports the optical, structural, electrical and dielectric properties of Poly (vinyl alcohol) thin films membranes with embedded ZnO nanoparticles (PVA/ZnO) obtained by the solution casting method at low temperature of deposition. Fourier Transform Infrared spectra showed the characteristics peaks, which correspond to O–H and Zn–O bonds present in the hybrid material. The X-ray diffraction patterns indicated the presence of ZnO structure into the films. The composite material showed low absorbance and a wide band of gap energy from 5.5 to 5.83 eV. The surface morphology for the thin films of PVA/ZnO was studied by Atomic Force Microscopy and Scanning Electron Microscopy. The electrical properties of the membranes were also characterized by current-voltage characteristics and the DC conductivity showed Arrhenius behavior with values of activation energy from 0.62 to 0.78 eV and maximum conductivity at 2.4 × 10⁻¹² S/cm. The dielectric properties of the nanocomposites were measured from low to high frequencies, and the results showed a high dielectric constant (ε) in the order of 10⁴ at low frequency and values from ε ≈ 2000 to 100 in the range of 1 KHz–1 MHz respectively. The properties of PVA/ZnO such as the high permittivity and the low temperature of processing make it a suitable material for potential applications in the development of flexible electronic devices.

The color exhibited by tungsten trioxide (WO₃) can be associated with both its stoichiometry and crystallinity. Correlation between the color exhibited by WO₃ powders and their purity and crystalline properties is reported in this paper. The WO₃ powders were deposited by evaporation of tungsten trioxide from the surface of a tungsten filament. The WO₃ powders exhibited three different shades of blue: navy, royal, and sky. The color of the WO₃ powders changed to white after thermal treatment at 500 °C for 30 min in an ambient atmosphere. Raman analyses showed that transition from amorphous to crystalline WO₃ started when the powders exhibited navy-blue color and ended when WO₃ powders exhibited a white color. Scanning electron microscopy analysis showed particle agglomeration characteristics in all WO₃ powders, even after they were thermally treated. The mechanism of deposition of WO₃ from the tungsten filament was suggested to be governed by thermal evaporation of tungsten trioxide from the surface of the oxidized tungsten filament.