A high-sensitivity and wide-range flexible pressure sensor based on micro-pyramid arrays and porous nanofiber networks.

Flexible pressure sensors have attracted significant attention as key components of smart wearable devices. Achieving both high sensitivity and a wide mechanical response range remains a major challenge. Here, we present an innovative flexible pressure sensor fabricated using silicon mold impression-transfer and electrospinning technologies. The sensor comprises two main components: a polydimethylsiloxane (PDMS) micro-pyramid array coated with silver nanowires as the electrode layer and a multi-layer porous nanofiber network formed by alternating polyacrylonitrile nanofibers and silver nanowires, serving as the sensing layer. The stepwise deformation of the PDMS micro-pyramidal array and the porous nanofiber network under pressure enables a wide mechanical response range while maintaining high sensitivity. Compared to flat-pattern designs, the micro-pyramid array significantly enhances sensitivity, achieving an ultra-wide detection range of 0-1600 kPa, a fast response time of 40 ms, a recovery time of 70 ms, and excellent durability over 2000 cycles. Furthermore, through Cell Counting Kit-8 (CCK-8) tests and live-dead cell staining experiments, we have verified the good biocompatibility of this novel sensor, providing safety assurance for subsequent applications. This work demonstrates a strategy for developing flexible, light weight, biocompatible, highly sensitive, and wide-range piezoresistive sensors by rationally designing micro-pyramid and multilayer nanofiber structures, demonstrating significant potential for medical applications, including human motion monitoring and bite force detection.