Mechanically Induced Surface Metallization of Ultraflexible Liquid Metal/SEBS Fibers for On-Demand and Multifunctional Physiological Monitoring

Fiber-based electronics are emerging as promising platforms for smart textiles, human-machine interfaces, and soft robotic systems, yet their practical deployment is hindered by limited conductivity and low structural robustness. Here, we report ultraflexible styrene-ethylene-butylene-styrene (SEBS) fibers homogeneously embedded with liquid-metal particles (LMPs) that undergo mechanically induced surface metallization, achieving an on-demand transition from insulating to conductive states for reliable motion sensing and high-fidelity electrophysiological monitoring. Micron-sized LMPs are homogeneously dispersed into an elastomer matrix to form a confined microstructure with strong antioxidation and leakage-free capabilities. Upon roller extrusion, the oxide shells of LMPs rupture, and eutectic gallium–indium extrudes and coalesces on the fiber surface, forming a stable and deformable metallized layer. This layer adheres strongly due to the high surface tension of liquid metal, imparting durable conductivity under repeated and large-scale deformation. These liquid metal fibers are further woven into permeable electronic textiles via a warp-weft manner, which simultaneously serve as strain sensors and epidermal bioelectrodes for stable motion sensing, and high-fidelity acquisition of surface electromyogram (sEMG), electrocardiogram (ECG), patterned visual evoked potentials (P-VEPs), and electrooculography (EOG) signals. This work establishes a scalable strategy to create on-demand, multifunctional fiber electronics for next-generation wearable bioelectronics.