From wool yarns to self-cleaning sweaters: color-retentive one-bath reactive dyeing and in situ TiO 2 loading for light-driven stain degradation

Developing self-cleaning wool textiles while maintaining color appearance and yarn durability remains challenging. A one-bath reactive dyeing and in situ TiO 2 -loading strategy was developed for wool yarns using Lanasol reactive dyes and tetrabutyl titanate. The treated yarns were knitted into sweater specimens to evaluate wearability and light-driven stain degradation. Scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) confirmed that fine Ti-containing species were deposited on the dyed wool fiber surface while the cuticle-scale structure was largely retained. The Ti content was approximately 1.0 wt% by EDS, and the surface Ti content reached 7.54 at.% by XPS. TiO 2 loading shifted the maximum degradation temperature from 317.7 to 321.9°C and increased the residual mass at 600°C from 11.02% to 17.11%. For Lanasol Red 6G, the optimized process increased the K/S value from 9.74 to 10.72, with a dye exhaustion of 93.5%. The TiO 2 -loaded dyed yarns retained their breaking tenacity and exhibited higher elongation at break and mean abrasion life than the dyed-only yarns. After ten washing cycles, 48.05% of the initial Ti content remained. Following 364 h of light irradiation, TiO 2 loading did not markedly accelerate fading. The ultraviolet protection factor increased from 10.9 to 14.3, with lower UVA and UVB transmittances. The TiO 2 -loaded sweater specimens also showed more effective light-driven removal of pitaya juice and soy sauce stains. This strategy provides a feasible route for integrating coloration, durability, UV shielding, and self-cleaning performance in wool garments.