Facile fabrication of Joule heating-induced highly elastic, durable, and reversible thermochromic wrapped yarn enabling stretchable dynamic colored displays

The colors of commercial textiles via dyeing or printing procedures were stationary, and these processes affect ecological environment. The existing thermochromic textiles via surface coating may involve poor permeability of vapor/air and inherent inelasticity, affected wearing comfort. Herein, we propose a facile and scalable fabrication strategy to manufacture Joule heating-induced elastic thermochromic wrapped yarn. The spiral geometrical configuration of yarn constituents and draw ratio of elastane filament (EF) are responsible for the exceptional stretchability of yarn. Benefitting from the distinct interlaced-helical structure and the introduction of EF, the yarn exhibited mechanical robustness following cyclic stretch. Further, it showed rapid, reversible thermochromic response and excellent service durability. More importantly, yarn-based embroidered patterns were fabricated as a proof-of-concept. They showed reversible thermochromic response with on/off voltage, and negligible color variation was seen during stretch. Such work makes elastic thermochromic yarn as a high-valuable proposition for further development of stretchable dynamic colored displays.