Highly sensitive and multifunctional piezoresistive sensor based on polyaniline foam for wearable Human-Activity monitoring

A highly stretchable and sensitive multifunctional piezoresistive sensor was reported. These sensors contain micro-cracked and hollowed-out polyaniline (PANI) foams which are supported by polydimethylsiloxane (PDMS). The cracked-PANI foam/PDMS (C-PF/PDMS) strain sensor shows high sensitivity with a gauge factor of similar to 10 and excellent linearity and high durability over 500 stretching-releasing cycles. The fabricated C-PF/PDMS pressure sensor exhibits a sensitivity of similar to 0.055 kPa(-1) in the pressure range of 0-5.0 kPa, a low detection limit of 4 Pa, a fast response time (similar to 60 ms), recovery time (similar to 90 ms) and the capability of detecting and distinguishing various mechanical stimuli including compression, shear and torsion forces. When the sensor is attached to the human body, it can function as a health-monitoring device by detecting various human motions such as the bending of fingers and wrist, phonation and the wrist pulse.