Scalable Imprinting of Flexible Multiplexed Sensor Arrays with Distributed Piezoelectricity-Enhanced Micropillars for Dynamic Tactile Sensing

The ongoing revolution of human-robot interactions and electronic skins has created new requirements for tactile sensors, including good mechanical flexibility, high sensitivity, and the availability of distributed pixels for detecting force distribution. Here, a highly sensitive flexible sensor array based on piezoelectricity-enhanced vertically aligned P(VDF-TrFE) micropillars is developed for dynamic tactile sensing. The core piezoelectric sensing micropillars are fabricated using a straightforward and scalable nanoimprinting technology and then sandwiched between a pair of cross electrode arrays to construct multiplexed sensor arrays. Due to the proposed structural design and nanoimprinting methodology, the sensor pixels exhibit uniform output generation, robust output stability, and scalable fabrication ability. In addition, taking advantage of the high compressibility and enhanced strain of the piezoelectric micropillars compared to planar films, the microstructured sensors show an enhanced sensitivity of 228.2 mV N-1 and a highly linear response to loads. By integrating the flexible sensor with a portable signal processing circuit, a complete tactile sensing system is successfully developed to provide clear intuitive user interfaces. The good flexibility and robust stability of the sensor arrays enable them to be attached onto curved surface for real-time tracking of dynamic force and imaging the force distribution.