Polypyrrole-Coated Graphene Oxide-Doped Polyacrylonitrile\nNanofibers for Stretchable Strain Sensors

Abstract

Stretchable\nyarn strain sensors demonstrate incomparable advantages\nfor application in wearable electronic devices, such as health monitors,\ninterfaces for human–computer interactions, and flexible robots,\nbecause of their good flexibility and ease of integration with other\ncomponents and fabrics. In this study, a graphene oxide (GO)-doped\npolyacrylonitrile nanofiber-coated hybrid yarn with a uniformly wavy\nstructure was used as the elastic substrate, and an in situ polymerized\npolypyrrole conductive polymer was applied to the nanofiber surface\nto construct a highly stretchable yarn strain sensor. The obtained\nsensor exhibited an advantageous wavy structure, which endowed it\nwith a wide monitoring range of 0–500%. The large number of\nnanofibers in the wave also provided a large contact area, which endowed\nthe sensor with an outstanding resistance change of 173.13 under stretching.\nIn addition, the sensor could monitor the bending deformation; the\nbending sensitivity was 16.6 at a bending degree of 4 cm. Meanwhile,\nthe sensor exhibited stable cycle durability, and only a small sensitivity\nloss rate was evident after 10,000 cycles during stretching and bending.\nIn addition, the sensor exhibited ideal weaveability and integration\nand could be easily woven into any fabric. Significantly, it could\nmonitor human muscle vibration and body movement, indicating its high\npotential for application in wearable electronic devices.