Investigation and optimization of the piezoelectric nanocomposite ZnO/PVVH/P(VDF-TrFE) for energy harvesting...

30/70 wt.% poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) / poly (vinylidene fluoride-co-trifluoroethylene) P(VDF-TrFE) polymer blend (PB) are prepared and doped with various content of Zinc oxide nanoparticle (ZnO NPs) using casting technique. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM), UV-Vis and Thermogravimetric analysis (TGA) are used for structural, optical and thermal properties investigation. XRD results revealed that the crystallinity degree of PB is enhanced from 83.8 to 92.3% upon increasing the ZnO NPs. FTIR analysis showed a shift in position of some characteristic bands, confirming the complexation between ZnO NPs and functional groups of PB. UV-Vis analysis showed that both direct and indirect energy gaps (E_dg/E_ig) are reduced from (4.08/2.34) for PB to (3.65/1.99) eV for 1.25 wt% ZnO/PB nanocomposite. Thermally stimulated depolarization current (TSDC) measurements demonstrated that the phase transition from ferroelectric to paraelectric phase occurred at 343 K for PB and increased to 350 K after embedding ZnO NPs. Thermal sampling (TS) technique is applied and thermodynamic parameters are estimated. Piezoelectric coefficient (d₃₃) is optimized from 12.8 pC/N for PB sample to 23.7 pC/N for 1wt.% ZnO/PB nanocomposite at 6.24 × 10⁵ Pa. Our results give a prediction for new piezoelectric material design capable for various energy harvesting applications.