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 ∼10 and excellent linearity and high durability over 500 stretching-releasing cycles. The fabricated C-PF/PDMS pressure sensor exhibits a sensitivity of ∼0.055 kPa −1 in the pressure range of 0–5.0 kPa, a low detection limit of 4 Pa, a fast response time (∼60 ms), recovery time (∼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.