Ultrasensitive and highly stretchable fibers with dual conductive microstructural sheaths for human motion and micro vibration sensing

Abstract

Conductive and stretchable fibers are important components of the increasingly popular wearable electronic devices as they meet the design requirements of excellent electrical conductivity, stretchability, and wearability. In this work, we developed a novel dual conductive-sheath fiber (DCSF) with a conductive sheath composed of a porous elastic conductive layer and cracked metal networks, thus achieving ultrahigh sensitivity under a large strain range. The core of the DCSF is made of thermoplastic polyurethane (TPU) elastic fiber wrapped in a porous stretchable conductive layer composed of carbon nanotubes (CNTs) and TPU. Next, a layer of gold film is deposited on the surface of the porous stretchable conductive layer by ion beam sputtering. Due to the fast response time of 184 ms and ultrahigh sensitivity in the 0–100% strain range (a gauge factor of 184.50 for a strain of 0–10%, 4.12 × 10⁵ for 10%–30%, and 2.80 × 10⁵ for 30%–100%) of the DCSF strain sensor, we successfully wove the fiber strain sensor into gloves and could realize the recognition of different hand gestures. Also the DCSF strain sensor can be applied to detect microvibrations efficiently. The demonstrated DCSF has potential applications in the development of smart wearable devices and micro vibration sensors.