Degradable Bioinspired Hypersensitive Strain Sensor with High Mechanical Strength Using a Basalt Fiber as a Reinforced Layer

Flexible strain sensors have received extensive attention due to their broad application prospects. However, a majority of present flexible strain sensors may fail to maintain normal sensing performances upon external loads because of their low strength and thus their performances are affected drastically with increasing loads, which severely restricts large-area popularization and application. Scorpions with hypersensitive vibration slit sensilla are coincident with a similar predicament. Herein, it is revealed that scorpions intelligently use risky slits to detect subtle vibrations, and meanwhile, the distinct layered composites of the main body of this organ prevent catastrophic failure of the sensory structure. Furthermore, the extensive use of flexible sensors will generate a mass of electronic waste just as obsoleting silicon-based devices. Considering mechanical properties and environmental issues, a flexible strain sensor based on an elastomer (Ecoflex)-wrapped fabric with the woven structure was designed and fabricated. Note that introducing a "green" basalt fiber (BF) into a degradable elastomer can effectively avoid environmental issues and significantly enhance the mechanical properties of the sensor. As a result, it shows excellent sensitivity (gauge factor (GF) ∼138.10) and high durability (∼40,000 cycles). Moreover, the reduced graphene oxide (RGO)/BF/Ecoflex flexible strain sensor possesses superior mechanical properties (tensile strength ∼20 MPa) and good flexibility. More significantly, the sensor can maintain normal performances under large external tensions, impact loads, and even underwater environments, providing novel design principles for environmentally friendly flexible sensors under extremely harsh environments.