Hollow ZnO nanorod in PVDF matrix for high-performance sensing, vibration energy harvesting and wearable application.

The hollow ZnO nanorods embedded in PVDF matrix were synthesized using a precise solvent casting technique, demonstrating superior performance and significantly enhancing the piezoelectric response, enabling the efficient detection of subtle mechanical stimuli such as gentle touch, bending, and vibration. The incorporation of ZnO nanorods facilitated the formation of the β-phase in PVDF, improved the material's crystallinity, and enhanced visible emission properties, contributing to its energy-harvesting efficiency. The ZnO/PVDF composite outperformed the PVDF film by approximately 6.5 times under repeated tapping energy harvesting conditions. Similarly, the ZnO/PVDF composite outperformed pure PVDF by charging the 10 µF capacitor to 5 V in just 12 s at a vibration frequency of 26.7 ± 0.38 Hz. The harvested energy was successfully deployed to power a standalone Bluetooth Low Energy (BLE) module, which acted as a transmission node for remotely monitoring vibration data from the ZnO/PVDF composite-based sensor. This innovative approach aligns with the advancements in Internet of Things (IoT) technology, highlighting its potential for energy-efficient wearable devices and remote sensing applications in vibration monitoring and other smart systems.