Preparation of photochromic wool fabrics based on thiol-halogen click chemistry

Photochromic fabric can change color when exposed to ultraviolet (UV) light and reversibly restore to its original color after the light disappears. As a kind of photochromic fabric, good stability and durable properties are necessary. In this study, a spirooxazine material with photochromic properties, 9'-(2-bromo-2-methylethoxycarbony1)-1,3,3-trimethyl-spiro[2H-indole-2,3'-[H]naphtha[2,1-b][1,4]oxazine], was synthesized and applied to wool fabric with chemical bonding. Tris (2-carboxyethyl) phosphine (TCEP) was firstly utilized as a reducing agent to generate thiol groups on the wool fabric. Then, these thiol groups will react with -Br groups of the spirooxazine via thiol-halogen click chemistry. The synthesized photochromic materials were characterized by FTIR, H-1 NMR and UV, and the as-prepared wool fabrics were characterized by FTIR and SEM. The results indicated that the photochromic materials have been successfully synthesized and the treated wool fabric has excellent photochromic properties, quick fading time and proper fatigue resistance while possessing good washing fastness and felting shrinkage performance.