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

Abstract

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.

Wearable Plant Sensors Based on Nanometer-Thick Ag Films on Polyethylene Glycol Terephthalate Substrates for Real-Time Monitoring of Plant Growth

“…In this study, inspired by the slit sensillum of scorpion, which possesses powerful sensing capability, − we developed a low-cost, large-scale fabrication process for developing wearable plant sensors. Without photolithography, inversion, etching, etc., a 82 μm “scorpion slit” was copied out and then a 120 nm-thick Ag layer was deposited, which exhibited ultrasensitive vibration-sensing capacity and could detect vibrations due to horizontal and vertical growth.…”

Nanofibrous Matrix Mediated Ultrasensitive Flexible Strain Sensor for Subtle Human Motion Monitoring

“…Flexible strain sensors are generally composed of two layers: a conductive functional layer sensitive to external strain and a flexible substrate layer for supporting and integrating with the active materials. 16,17 One effective strategy to improve the performance of flexible strain sensors within subtle strain variation is to manipulate the functional layers with complex microstructures to generate significant structural and conductivity variations even with small strain changes. 18,19 So far, various microstructures have been explored, including micropyramids, 20 porous, 21 microcracks, 22 and biomimetic hierarchical structures.…”

“…Flexible strain sensors are generally composed of two layers: a conductive functional layer sensitive to external strain and a flexible substrate layer for supporting and integrating with the active materials. , One effective strategy to improve the performance of flexible strain sensors within subtle strain variation is to manipulate the functional layers with complex microstructures to generate significant structural and conductivity variations even with small strain changes. , So far, various microstructures have been explored, including micropyramids, porous, microcracks, and biomimetic hierarchical structures . In particular, microcrack structures originating and propagating in brittle thin films along the deformation of underlying flexible supporting layers could significantly enhance the sensitivity of sensors within the subtle strain range by releasing the accommodated stress at the stress concentrated areas. , In this view, Li et al developed a carbon black (CB)/carbon nanotube (CN)-coated paper strain sensor with surface microcracks using the mismatches between the CB/CN coating and substrate materials based on the thermal expansion coefficient and elastic modulus during drying.…”