Transparent\nand Waterproof Ionic Liquid-Based Fibers for Highly Durable Multifunctional\nSensors and Strain-Insensitive Stretchable Conductors

Abstract

Ionic\nliquids (ILs) are regarded as ideal components\nin the next generation of strain sensors because their ultralow modulus\ncan commendably circumvent or manage the mechanical mismatch in traditional\nstrain sensors. In addition to strain sensors, stretchable conductors\nwith a strain-insensitive conductance are also indispensable in artificial\nsystems for connecting and transporting electrons, similar to the\nfunction of blood vessels in the human body. In this work, two types\nof ILs-based conductive fibers were fabricated by developing hollow\nfibers with specific microscale channels, which were then filled with\nILs. Typically, the ILs-based fiber with straight microchannels exhibited\na high strain sensitivity and simultaneously rapid responses to strain,\npressure, and temperature. The other ILs-based fiber with helical\nmicrochannels exhibited a good strain-isolate conductance under strain.\nDue to the high transparency of ILs along with the sealing process,\nthe as-prepared ILs-based fibers are both highly transparent and waterproof.\nMore importantly, owing to the low modulus of ILs and the core–shell\nstructure, both conductive fiber prototypes demonstrated a high durability\n(>10 000 times) and a long-term stability (>4 months).\nUltimately, the ILs-based fibrous sensors were successfully woven\ninto gloves, flaunting the ability to detect human breathing patterns,\nsign language, hand gestures, and arm motions. The ILs-based strain-insensitive\nfibers were successfully applied in stretchable wires as well.