Scorpion-inspired multi-scale contact enabled multifunctional piezoresistive pressure sensor based on hybrid nanofiber decoration

Inspired by the slit organs of scorpions, an array narrow orifice configuration (ANOC) piezoresistive foam sensors are developed by decorating hybrid polypyrrole (PPy)/ carbon nanotubes (CNT) nanofibers on the foam strut. The developed ANOC composite foam exhibits a unique multi-scale contact sensing mechanism enabled by the macro-scale internal dome structures, the micro-scale struts of the porous foam, the nano-scale PPy/CNT hybrid conductive networks, and the nano-scale friction of the rough CNT/PPy hybrid nanofibers (NFs), which rendered the ANOC composite foam an ultra-high sensitivity of 1.8 kPa −1 at low pressure within 1.5 kPa. When used as a piezoresistive pressure sensor, the ANOC composite foam exhibits a wide detection range (0 %-70 %), fast response/recover time (120/90 ms), and long-term stability and fatigue resistance (over 80000 s), and demonstrated capability to monitor various human activities. A smart cushion integrated with an array of foam sensors can accurately identify the human sitting positions and posture rectifying. Moreover, owing to the highly porous conductive network and the doped ions, the ANOC composite foam can generate energy from saline water and serve as a water-induced energy generation (WIEG) device for direct energy supply. This research paves the way for the development of multifunctional high-performance.