Construction of “island-bridge” microstructured conductive coating for enhanced impedance response of organohydrogel strain sensor

Abstract

Flexible conductive hydrogels (CHs) have received widespread attention in the field of wearable strain sensor, electronic skin, and artificial intelligence owing to their excellent stretchability, biocompatibility, and real-time sensing performance. However, it still remains a critical challenge to design and construct the satisfactory wearable strain sensor integrated with high sensitivity, wide sensing range, and environmental stability, especially at extreme temperatures. Herein, ionic conductive polyacrylamide/sodium alginate nanocomposite organohydrogel anchored with electronic conductive “island-bridge” microstructured carbon nanotubes (CNTs) conformal coating was designed and fabricated for high-performance strain sensor, of which the existence of “island-bridge” microstructured electronic conductive layer and its special structure evolution upon external stretching can significantly enhance the alternating current impedance response behavior of the sensor, featuring with a high sensitivity of 76.54 at 600 % strain, wide sensing range (0–600 % strain), fast responsiveness (110 ms), extremely low detection limit (0.1 %), and favorable stability and reproducibility of over 3200 cycles. Meanwhile, the resultant organohydrogel strain sensor can precisely detect and differentiate complicated human activities even at the environment temperatures of −30 °C and 50 °C, opening a promising avenue for next-generation smart wearable electronics.