A highly sensitive, multifunctional, and wearable mechanical sensor based on RGO/synergetic fiber bundles for monitoring human actions and physiological signals

We propose a flexible, multifunctional and highly sensitive mechanical sensor that can monitor various mechanical strains induced via stretching, pressing, bending, vibration and torsion. The sensor demonstrates a well-designed conductive fiber alignment based on synergetic fiber bundles coated with a thin reduced graphene oxide (RGO) layer (SF/RGO). When stretched, the fiber bundles fracture into gaps, islands, and bundles bridging the gaps; thus, allowing the conductive fiber bundles to serve as mechanical sensors capable of detecting trace tensile strain down to 0.05% with a high sensitivity (Gauge Factor = -8.9). Furthermore, the sensor also demonstrated high durability, wide sensing range (75% for strain, and 36 kPa for pressure). These remarkable features endow our sensing devices to monitor full-range human motions from subtle bio-signals e.g. pulse wave, phonation and respiration to human physical actions e.g. finger typing, bending or grasping. Furthermore, large-area sensor arrays are successfully fabricated to spatially map pressure stimuli, demonstrating great potential for applications in wearable electronics and healthcare.