Environmentally friendly and biodegradable ultra-sensitive piezoresistive sensors for wearable electronics applications.ACS Appl Mater Interfaces 2020AA
Highly sensitive, flexible sensors that can be manufactured with minimum environmental footprint and be seamlessly integrated in wearable devices are required for real-time tracking of complex human movement, gestures and health conditions. This study reports on how biodegradation can be used to enhance the sensitivity and electromechanical performance of piezoresistive sensors. Poly(glycerol sebacate) (PGS) elastomeric porous sensor was synthetized, blended with multiwall carbon nanotubes (MWCNTs) and sodium chloride (NaCl). Due to their unique porous characteristics, a single linear behavior over a large range of pressures (≤ 8 kPa) and an increase in their sensitivity from 0.12 ± 0.03 kPa-1 up to 8.00 ± 0.20 kPa-1, after 8 weeks in a simulated body fluid media was achieved. They can detect very low pressures (100 Pa), with negligible hysteresis, reliability, long lifetime (>200,000 cycles), short response time (≤ 20 ms) and high force sensitivity (≤ 4 mN). The characteristics of the developed foam sensors match the sensing characteristics of the human finger to pave the way towards low foot-print wearable devices for applications including human movement and condition monitoring, recreation, health and wellness, virtual reality and tissue engineering.