Biomass carbon nanosphere-based piezoresistive flexible pressure sensors for motion capture and health monitoring

Biomass carbon-based flexible sensors have shown significant potential in various applications. Indeed, biomass carbon-based flexible sensors, such as carbonized cotton fabrics, exhibit limitations in terms of sensitivity and response speed. Herein, a kind of biomass carbon nanosphere-based flexible pressure sensor was proposed and developed by embedding biomass carbon nanospheres on the skin-hair structures of the polydimethylsiloxane surface. The carbon nanospheres were obtained through the carbonization of cuttlefish ink. Owing to the skin-hair structures fabricated on the surface of the composite films, the sensors achieve a sensitivity of 135.2 kPa⁻¹ in the pressure range of 0–1 kPa. In addition, the sensors exhibit a short response (43 ms) and recovery time (23 ms). With these properties, the sensors can capture and monitor various motions as well as the characteristic waveforms of the wrist pulse, such as the percussion wave (P wave), tidal wave (T wave), and diastolic wave (D wave).