Multifunctional and highly stretchable gold-leaf/WPU/TPU fibers by a rolling adhesive method

Abstract

Flexible conductive fibers have attracted significant attention due to their excellent mechanical and electrical properties. In this study, a new rolling adhesive technique was introduced to fabricate flexible conductive fibers with a nano-gold leaf on thermoplastic polyurethane (TPU) fiber using waterborne polyurethane (WPU) as an inner adhesive layer. The gold-leaf/WPU/TPU (GLWT) fiber with a single gold sheath layer can be applied as a resistive strain sensor with high sensitivity (GF = 130) at large strain (80%) to detect human motion. In addition, we have successfully woven GLWT fibers into gloves by taking advantage of the knittability of the fibers to enable the identification of various hand gestures. The GLWT fibers can be thermoformed into helices to achieve excellent electrical properties (Q = 123) over a wide range of strains (1600%). It is worth noting that GLWT fibers can be prepared into capacitive pressure sensing arrays by staggered placement, which have the ability to identify the shape of objects. We also fabricated a GLWT fiber with two gold-leaf sheath layers, which shows a capacitive response with good linearity (0.999) up to 60% strain and GF of 0.8. Overall, GLWT fibers have considerable potential in the field of flexible electronic devices due to their simple manufacturing process and multifunctional applications.