Textile‐Grade Mechanoluminescent Fibers by Continuous Wet Spinning

ABSTRACT Mechanoluminescent (ML) fibers that transduce mechanical stimuli into visible light without external power or circuitry offer a bottom‐up route toward intelligent textile systems. Despite diverse fabrication strategies, most reported ML fibers exhibit insufficient mechanical robustness and scalability, hindering their transition to textile‐grade implementation. Here, we report the first continuous wet‐spun manufacturing process for ML fibers. The composite fibers, consisting of ZnS:Mn particles homogeneously embedded within a thermoplastic polyurethane (TPU) matrix, achieve high structural and optical quality owing to improved particle dispersion via ball milling, emission tuning through Mn 2+ stoichiometry control, and synergistic optimization enabled by coordinated geometric and compositional design. The resulting fibers reach lengths up to 50 m, exhibit a tensile strength of ∼24 MPa with elongation exceeding 560%, and generate rapid luminescence (<0.3 s). They maintain stable output over hundreds of deformation‐recovery cycles, withstand repeated washing, and deliver reproducible impact emission in close agreement with finite‐element modeling, demonstrating great reliability and well‐understood stress‐light coupling mechanism. These attributes enable a successful transition into functional fabrics, enabling real‐time visualization of joint motion and external impacts through biomotion‐activated optical sensing. This work establishes a scalable and versatile route for ML textiles, opening new possibilities in wearable monitoring, rehabilitation, and safety protection.