Bioinspired flexible piezoresistive sensor for high-sensitivity detection of broad pressure range

The human skin has the ability to sense tactile touch and a great range of pressures. Therefore, in prosthetic or robotic systems, it is necessary to prepare pressure sensors with high sensitivity in a wide measurement range to provide human-like tactile sensation. Herein, we developed a flexible piezoresistive pressure sensor that is highly sensitive in a broad pressure range by using lotus leaf micropatterned polydimethylsiloxane and multilayer superposition. By superposing four layers of micropatterned constructive substrates, the multilayer piezoresistive pressure sensor achieves a broad pressure range of 312 k Pa, a high sensitivity of 2.525 k Pa-1, a low limit of detection（LOD） of <12 Pa, and a fast response time of 45 ms.Compared with the traditional flexible pressure sensor, the pressure range of this sensor can be increased by at least an order of magnitude. The flexible piezoresistive pressure sensor also shows high robustness: after testing for at least 1000 cycles,it shows no sign of fatigue. More importantly, these sensors can be potentially applied in various human motion detection scenarios, including tiny pulse monitoring, throat vibration detection, and large under-feet pressure sensing. The proposed fabrication strategy may guide the design of other kinds of multifunctional sensors to improve the detection performance.