Enhanced Piezoelectric and Mechanical Performance of Flexible ZnO Nanorod/PVDF Composite Sensors: From Nanoscale Mapping to Macroscopic Durability

Polyvinylidene fluoride (PVDF) nanocomposites embedded with inorganic fillers have become leading candidates for self-powered flexible electronics. However, understanding the interaction between nanoscale piezoelectric domains and macroscopic mechanical durability remains a challenge for the practical development of sensors. This work provides a comprehensive investigation into the mechano-electrical properties of Zinc Oxide (ZnO) nanorod/PVDF flexible composite films. Structural characterization confirmed the nucleation of the electroactive β-phase, reaching a maximum of 97.3% in the 5 wt% composite. Field Emission Scanning Electron Microscopy (FESEM) confirmed the homogeneous dispersion of nanorods at this optimal loading, while cross-sectional analysis revealed a dense microstructure indicative of strong interfacial compatibility. Piezoresponse Force Microscopy (PFM) revealed that well-dispersed nanorods function as piezo-active hotspots, significantly enhancing local domain switching and amplitude compared to the pristine polymer. Furthermore, nanoindentation and tensile testing demonstrated that the nanorods serve as dual-functional reinforcing agents. The optimized composite showed a 39% increase in elastic modulus and a 56% improvement in toughness (1.72 MJ/m³) without sacrificing flexibility. The optimized nanocomposite combines enhanced local piezoelectric response with superior mechanical robustness, establishing it as a durable material system suitable for next-generation flexible electronic applications.