Scorpion-inspired dual-bionic, microcrack-assisted wrinkle based laser induced graphene-silver strain sensor with high sensitivity and broad working range for wireless health monitoring system

Scorpions, through ruthless survival of the fittest, evolve the unique ability to quickly locate and hunt prey with slit receptors near the leg joints and a sharp sting on the multi freedom tail. Inspired by this fantastic creature, we herein report a dual-bionic strategy to fabricate microcrack-assisted wrinkle strain sensor with both high sensitivity and stretchability. Specifically, laser-induced graphene (LIG) is transferred from polyimide film to Ecoflex and then coated with silver paste using the casting-and-peeling and prestretch-and-release methods. The shape-adaptive and long-range ordered geometry (e.g., amplitude and wavelength) of dual-bionic structure is prestrain-tuned to optimize the superfast response time (similar to 76 ms), high sensitivity (gauge factor = 223.6), broad working range (70%-100%), and good reliability (> 800 cycles) of scorpion-inspired strain sensor, outperforming many LIG-based materials and other bionic sensors. The alternate reconnect/disconnect behaviors of slit-organ-like microcracks in the mechanical weak areas initiate tremendous resistance changes, whereas the scorpion-tail-like wrinkles act as a "bridge" connecting the adjacent LIG resistor units, enabling reversible resilience and unimpeded electrical linkages over a wide strain range. Combined with the self-developed miniaturized, flexible, and all-in-one wireless transmission system, a variety of scenarios such as large body movements, tiny pulse, and heartbeat are real-time monitored via bluetooth and displayed in the client-sides, revealing a huge promise in future wearable electronics.