Development of a bio-inspired manufacturing framework for piezoelectric sensors

This study proposes and experimentally validates a bio-inspired manufacturing strategy for piezoelectric sensors that emulates the modular and decoupled formation mechanisms observed during insect metamorphosis. This process enables independent fabrication and optimization of the mechanical structure, piezoelectric element, and electrode interconnects, followed by low-temperature heterogeneous integration through heat-activated bonding, thereby overcoming persistent challenges in the conventional fabrication processes of piezoelectric sensors. A series of characterizations confirmed that the laser micromachining of polyvinylidene difluoride (PVDF) and polyimide (PI)-Cu films maintained material integrity, while adhesive bonding achieved uniform, defect-free interfaces. Proof-of-concept piezoelectric accelerometers fabricated via the proposed process exhibited a mean sensitivity of 3.17 pC/g, 5% bandwidth of 350 Hz, and intersample deviation below 5%, matching the performance of devices fabricated using classical microelectromechanical system (MEMS) techniques. Furthermore, wearable tests demonstrated the ability of the sensors to detect subcutaneous vocal-fold vibrations and distinguish between different spoken words, verifying their functional stability and application feasibility. The results establish a generalizable and low-temperature polymer-based manufacturing framework for creating complex, highly reliable piezoelectric sensors with direct implications for the future development of multimodal, flexible, and bio-integrated sensing systems.