The development of flexible electronic skins with high performance and multifunctional sensing capabilities is of great significance for applications ranging from healthcare monitoring to artificial intelligence. To mimic and surpass the high-gauge-factor sensing properties of human skin, structure design and appropriate material selection of sensors are both essentially required. Here, we present an efficient, low-cost fabrication strategy to construct an ultra-highly sensitive, flexible pressure sensor by embedding the aligned nickel-coated carbon fibers (NICFs) in a polydimethylsiloxane (PDMS) substrate. Our design substantially contributes to ultrahigh sensitivity through the parallel circuit formed by aligned NICFs as well as surface spinosum microstructure molded by sandpaper. As a result, the sensor exhibits excellent sensitivity (15 525 kPa-1), a fast response time (30 ms), and good stability over 3000 loading-unloading cycles. Furthermore, these superior sensing properties trigger applications in water quality and wave monitoring in conjunction with mechanical flexibility and robustness. As a precedent for adjusting the sensitivities of the sensor, the NICFs/PDMS sensor provides a promising method for multiscenario healthcare monitoring, multiscale pressure spatial distribution, and human-machine interfacing.
Keywords: aligned fibers; flexible electronics; high sensitivity; magnetic orientation; piezoresistance sensor; tactile sensor.