In this work, new samples of PVA-TiO₂/Cu nanocomposites were prepared via the casting method. The prepared samples were examined using different analytical methods. An XRD analysis showed the semi-crystalline nature of the PVA polymer, as well as showing a decrease in the degree of the crystallinity of the PVA structure as a result of the addition of the mixed nanoparticles. TEM images indicate the spherical shape of the Cu NPs, with a size ranging from 2 to 22 nm, and the rectangular shape of the TiO₂ NPs, with a size ranging from 5 to 25 nm. It was evident via FTIR measurements that there were interactions between the functional groups of the PVA and the TiO₂/Cu NPs. The optical properties of the PVA nanocomposites were improved with an increase in the content of the TiO₂/Cu nanoparticles, as shown via a UV/Vis analysis. DSC curves showed an improvement in the thermal stability of the PVA-TiO₂/Cu nanocomposites after the embedding of the TiO₂/Cu nanoparticles. It was evident using impedance spectroscopy that the AC conductivity was improved by adding the TiO₂ and Cu nanoparticles to the polymeric matrix. The maximum AC conductivity was found at 1.60 wt.% of TiO₂/Cu nanoparticles in the PVA polymer, and this was 13.80 × 10⁻⁶ S/cm at room temperature. Relaxation occurred as a result of the charge carrier hopping between the localized state and the correlated barriers hopping model, describing the dominant mechanism, as presented in an electrical modulus analysis. These results indicate that the PVA-TiO₂/Cu nanocomposite samples can be used in energy storage capacitor applications and in the alternative separator-rechargeable lithium-ion battery industry.

Using a conventional casting method, flexible polymeric film nanocomposites composed of PMMA (polymethyl methacrylate), PS (polystyrene), PVC (polyvinyl chloride) and ZnO nanoparticles were synthesized. Fourier transform infrared (FTIR) spectroscopy identified distinct peaks corresponding to vibrational groups in the prepared samples. Upon doping the PVC/PMMA/PS blend with varying concentrations of ZnO NPs (2.5–10 wt%), most absorption intensities tend to diminish progressively as the ZnO contents have been increased to 5 wt%. Changes in FTIR vibrational bands indicated interactions between the PVC/PMMA/PS/ZnO nanocomposite constituents. The XRD patterns of the ZnO NPs-based composites have exhibited the same peaks of the pure blend; however, there is a notable increase in broadness and a significant reduction in intensity as the weight percentage of ZnO NPs rises from 2.5 to 10. This observation indicates the development of interactions between the polymer and nanoparticles. The redshift seen in the absorption edge of the samples filled with ZnO provided strong evidence that charge transfer complexes had formed inside the polymeric matrix. The indirect and direct energy gaps for allowable transitions decreased with increasing ZnO NP concentrations, ranging from 3.88 eV and 4.87 eV in the pure blend to 3.31 eV and 4.67 eV, respectively. The σ_AC value at 100 Hz was 8.41 × 10⁻¹³ S·cm⁻¹ and increased with frequency, reaching 5.12 × 10⁻⁹ S·cm⁻¹ at 10⁶ Hz. Also, a modest improvement in σ _AC values is observed with the increase of ZnO NPs loading. The increase in conductivity can be ascribed to the improved amorphous nature of the synthesized nanocomposite facilitated by the incorporation of ZnO NPs. Dielectric studies showed that the best improvement was attained for the PVC/PMMA/PS/5 wt% of ZnO nanocomposite sample. Further, its imaginary part (ε″) exhibited a constructive decrease in its value with the increase in the ZnO loadings. These findings recommend these nanocomposites for potential applications in optoelectronics and energy storage devices.