Flexible and Breathable Piezoresistive Sensors Based on Reduced Graphene Oxide/Silk Fiber/Carbon Cloth Composites for Health Monitoring

Flexible electronic devices, particularly wearable piezoresistive sensors, have garnered considerable research attention due to their potential applications in medical diagnosis, human-machine interaction, and motion monitoring. However, it remains a pressing challenge and highly demanded for the fabrication of piezoresistive sensors with outstanding sensing performance, breathability, and degradability at the end of their life cycle. In this study, we prepared high-performance piezoresistive sensors with breathability and degradability. These sensors were made with reduced graphene oxide/silk fibers (rGO/SFs) as the sensing materials and carbon cloth (CC) as the interdigital electrodes. Taking advantage of the porous structures of the rGO/SFs composite and CC, the rGO/SFs/CC sensor demonstrated a low detection limit (1 Pa), substantial sensitivity across a broad response range (over 500 kPa), rapid response (92 ms), and quick recovery time (26 ms). Moreover, it maintained excellent electromechanical reliability even after undergoing 10,000 loading-unloading cycles. Furthermore, these sensors also exhibited other favorable attributes, including breathability, degradability, exceptional detection capabilities toward various deformations (compression, distortion, and bending), and exceptional stability across different loading frequencies and temperatures. The sensor successfully served in real-time monitoring and identification of full-scale body motions.