Flexible PVDF-ZnO Composite Sensor with High Sensitivity and Piezoelectric Response for Enhanced Acoustic Emission Detection

Flexible sensors are increasingly essential in applications requiring adaptability to complex surfaces and resilience under mechanical stress, yet traditional rigid sensors often lack these capabilities, limiting their effectiveness. This study addresses these challenges by enhancing the piezoelectric properties of PVDF by incorporating ZnO nanorods, creating a flexible composite sensor with superior sensitivity. A homogenous PVDF-ZnO composite was fabricated via an optimized casting method, achieving up to 97% beta phase for high piezoelectric response. FESEM, XRD, and FTIR characterization confirmed uniform ZnO dispersion and phase transition The sensor was later evaluated for its effectiveness in acoustic emission detection for nondestructive testing applications. A pencil lead break test demonstrated a substantial voltage output (23 mV), surpassing a conventional PZT sensor. These findings highlight the potential of PVDF-ZnO composites for high-sensitivity acoustic emission sensing applications.