Tunable flexible pressure sensor based on bioinspired capillary-driven method

Abstract

Flexible pressure sensors are highly desired in a wide variety of areas including artificial intelligence and healthcare monitoring. Amidst them, capacitive pressure sensors are advantaged for simple configuration and fast reponse speed. However, they suffer from some restrictions such as limited and fixed sensitivity as well as unsatisfactory robustness. Herein, a tunable flexible capacitive pressure sensor is realized by bioinspired capillary-driven method. The dielectric layer with double-side microstructure is developed with polycarbonate template molding (PCTEM) driven by capillary force, while the bottom and top electrodes are fabricated by a colorless polyimide (CPI) film coated with silver nanowires. The sensor exhibits a tunable sensitivity from 0.189 k Pa−1 to 5.821 k Pa−1 with an ultralow limit of detection (LOD) of ~1.5 Pa and a fast response time of ~30 ms. The sensor offers a configuration with a thickness of 130 μm and excellent robustness for fatigue test of 200,000 cycles. The pressure sensor fabricated by the PCTEM method allows sensitive and tunable pressure sensing in soft robotics and human-machine interaction. Also, the bioinspired capillary-driven PCTEM strategy may offer a guideline to design other microstructures with improved performance for varied flexible sensors.