Liquid Metal Fiber-Based High-Sensitivity Strain and\nPressure Sensors Enhanced by Porous Structure

Fiber-based\nsensors have garnered increasing attention due to their\nremarkable comfort and adaptability to complex surfaces. Nonetheless,\nenhancing the sensitivity of fiber-based sensors remains a formidable\nchallenge. In this study, a liquid metal porous fiber-based strain\nand pressure sensor was designed for monitoring human joint movement,\npressure magnitude, and distribution as well as object proximity detection.\nA hollow double-layer fiber was fabricated via coaxial wet spinning,\nemploying a spinning solution comprising a mixture of sodium chloride\nparticles and thermoplastic polyurethane (TPU) solution, along with\nTPU solution and deionized water, from the outermost to the innermost\nlayer. Subsequently, liquid metal was injected into the hollow fibers\nto obtain liquid metal porous fiber-based strain and pressure sensors.\nRemarkably, the pressure-sensing sensitivity was improved by 6.00\n± 1.70 and 3.42 ± 0.31 times in the pressure ranges of 0–0.06\nand 0.06–8 MPa. The incorporation of a porous structure significantly\nenhanced the sensitivity of the pressure sensor. Furthermore, the\ndeveloped sensor exhibited exceptional adaptability to pressure and\nstrain stimuli across different magnitudes and application speeds\nwhile demonstrating remarkable stability and fatigue resistance, withstanding\nover 1000 cycles. The methodology established in this study offers\nan effective strategy for the design and fabrication of high-performance\nfiber sensors.