Bioinspired hierarchical polydimethylsiloxane/polyaniline array for ultrasensitive pressure monitoring

Flexible pressure sensors based on contact resistance change have the advantages of low temperature dependence and fast response, but their sensitivity and pressure sensing range are limited by the deformation level of the surface structures. Inspired by the hierarchical structure of insect touch receptors, where the primary mechanoreceptor organs have the basic tactile sensing elements and the secondary bristles or tactile hairs maximize signal transduction, we design a hierarchical structure-based pressure sensor consisting of polydimethylsiloxane (PDMS) micropillars and conductive polyaniline (PANI) nanoneedles. Owing to this unique structure, this sensor exhibits ultrahigh sensitivity of 258.7 kPa−1, ultralow detection limit of 0.68 Pa, fast response time of 30 ms and excellent cycle stability over 10,000 cycles. In addition, the pressure sensor shows promising potential in human physiological signal monitoring, such as wrist pulse, throat behavior, finger bending and biceps movements. Evidently, this hierarchical PDMS/PANI structure-based piezoresistive sensor provides an alternative design path for high-performance pressure sensors.