Highly sensitive and stretchable strain sensor based on modified carboxylic carbon nanotubes/chitosan/polyurethane yarn

Although several strain sensors based on carbon nanotubes have been reported, it is still a great challenge to fabricate strain sensors possessed with large workable strain range, high sensitivity and stability. Herein, we developed a highly elastic strain and high sensitivity sensor based on stretchable spandex yarns manufactured by an easy layer-by-layer assembly method. Effects of multi-walled carboxylic carbon nanotubes and chitosan on sensor's properties were investigated. The prepared sensor exhibited fascinating comprehensive sensing performance, including large workable strain range (∼115%), superior sensitivity (gauge factor up to 159 at 0–40% strain and 8175 over 100% strain), In addition, it still exhibited good work stably after 3500 cycles at strain of 50%. The sensor can detect both large and small scale human motions, including joint movement, phonation, swallowing, and drinking.