Tailoring Structural, Optical, and Dielectric Properties of PVC/PMMA/PS/ZnO Nanocomposites for Capacitive Energy Storage Applications

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.