Scalable topological-entanglement conductive coaxial fibers with superior durability for wearable strain sensing and triboelectric fabric

Abstract

Although flexible, stretchable, and conductive core-sheath structured smart fibers have propelled to the forefront research in wearable strain sensors and self-powered electronics, challenges related to scalability, complexity, and mechanical durability remain. In this study, we propose a strategy for the scalable production of conductive coaxial fiber (CCF) with superior durability through one-step direct wet spinning coherent solutions. By introducing the polystyrene-block-polyisoprene-block-polystyrene phase in both inner and outer layers, CCFs feature an interleaved topology and share a similar modulus, successfully resolving the issue of layer separation over time. They can endure up to 15000 cycles with no damage at a strain of 100%. In addition, the topological entanglement CCF as a strain sensor exhibits a broad operational range of up to 398.3% strain, outstanding sensitivity (i.e., gauge factor = 6713 at 398.3% strain) and swift response time (248 ms). Enhanced by machine learning, the system achieves a high accuracy rate of 95% in gait recognition and 100% in American Sign Language identification. Furthermore, the CCF can function as a wearable triboelectric nanogenerator (TENG) for self-powered sensing and mechanical energy harvesting. This study represents a significant step toward the development of multifunctional micro-wearable electronic devices, which hold immense promise for medical sensing and energy harvesting in smart wearable electronics, human-computer interaction, and artificial intelligence.