Three-dimensional light-weight piezoresistive sensors based on conductive polyurethane sponges coated with hybrid CNT/CB nanoparticles

Low-cost production of piezoresistive strain/pressure sensor with high sensitivity, fast response, good stability and repeatability is still one of the critical challenges for the practical applications of flexible piezoresistive materials in human motion detection, health monitoring, wearable electronics, and e-skins. Herein, we develop a simple and efficient route to fabricate the three-dimensional (3D) light-weight piezoresistive sensing materials via the surface coating the polyurethane (PU) sponge with hybrid carbon nanotube (CNT)/carbon black (CB) nanoparticles. It is found that the CNT/CB@PU sponge exhibits high sensitivity, fast response, instant recovery, and stable compression-release signals to the strain/pressure stimuli, which can be designed into the versatile piezoresistive sensors to detect various human motions within a wide strain range, such as blowing, swallow, deep breath, finger bending, elbow bending, and knee bending. More importantly, this work illuminates the sensing mechanisms of conductive sponges coated with different dimensional nanoparticles and paves a new way toward large-scale and low-cost production of wearable pressure/strain sensors.

Automated summary

The study introduces a simple and efficient method for fabricating lightweight three-dimensional piezoresistive sensing materials through coating CNT/CB@PU sponge, which demonstrates high sensitivity, fast response, instant recovery, and stable characteristics for designing versatile piezoresistive sensors to detect various human motions.