Super-elastic and multifunctional core-sheath EGaIn fibers for wearable motion detection and visual electrophysiologic monitoring

Fiber-based wearable electronics, distinguished by their remarkable flexibility and robust performance, have emerged as a focal point in healthcare and soft robotics. While significant strides have been made in advancing fiber-based wearable electronics, pursuing multifunctional integration, particularly in areas such as personal health monitoring continues to present significant challenges. In this work, we report the successful fabrication of ultra-elastic and multifunctional core-sheath EGaIn microfibers tailored for wearable motion detection and visual electrophysiologic monitoring. These highly conductive fibers are characterized by an intriguing core-sheath structure, achieved through the uniform coating of EGaIn liquid metal on wet-spun elastomeric microfibers, which are priorly magnetron sputtered with gold nanoparticles (Au NPs) for fast alloying with EGaIn. Prepared core-sheath EGaIn microfibers possess numerous micro-wrinkles on the surface via a simple pre-stretching treatment, thus demonstrating an exceptional sensitivity (GF = 108.3), a fast response time of 82 ms, and remarkable stability. Their superior electromechanical stability and sensitivity under various strain conditions enable reliable and real-time detection of human motion signals, electrooculography (EOG) signals, and visual evoked potentials (VEP). This research offers a novel approach to the multifunctional integration of high-performance fiber-based electronics.