The influence of copper oxide nanoparticles (CONPs) on the polymorphism of poly(vinylidene fluoride) (PVDF) was systematically investigated in this work. Copper oxide nanoparticles having an average diameter of 60 nm were synthesized by a simple, cost effective, environmentally benign modified hydrothermal method. Then a series of copper oxide nanoparticles incorporating flexible, self-standing PVDF films were prepared by the solution casting technique. The impact of the CONP loading on the structural and morphological properties of PVDF were studied by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The thermal properties of the sample were investigated by differential thermal analysis, thermogravimetric analysis and differential scanning calorimetry techniques. The incorporation of CONPs leads to faster crystallization and thereby promotes the formation of electroactive β-phase enriched PVDF films. Strong interfacial interactions between the negatively charged nanoparticle surface and positively charged –CH₂ dipoles of the PVDF lead to a significant enhancement of the electroactive β-phase. The 5 wt% CONP–PVDF composite film exhibits a maximum β-phase fraction of 90% due to having the highest interfacial area between the well-dispersed nanoparticles’ surfaces and the polymer.