Lotus leaf inspired superhydrophobic rubber composites for temperature stable piezoresistive sensors with ultrahigh compressibility and linear working range

Piezoresistive sensors have promising applications in wearable electronics; however, developing multi-functional piezoresistive sensors that possess ultrahigh compressibility and linear working range and could be used in tough environment (e.g., high humidity, corrosive media and low temperatures) remains a challenge. Herein, a flexible electrically conductive polymer foam composite (CPFC) with the lotus leaf inspired microstructure is prepared by anchoring carbon nanotubes (CNTs) onto the skeleton of the polymer foam with the assistance of ultrasonication and simultaneous non-solvent induced phase separation (NIPS). Hemisphere arrays are produced on the skeleton of the polymer foam, while CNTs are decorated on the surface of these arrays, forming conductive network. The obtained superhydrophobic CPFC exhibits excellent anti-corrosive and photothermal conversion performance, making it possible to be used in some harsh environment. When used as the piezoresistive sensor, the CPFC exhibits stable electrical conductivity, extremely high compressibility and linear working range (up to 90%), superb sensing stability and durability (over 2300 cycles). Furthermore, the piezoresistive sensing performance is impervious to the ambient temperature, and the CPFC sensor can work in the temperature from −20 ℃~80 ℃ with stable sensing signals. Also, the CPFC can detect various human body movements even in the corrosive condition.