Robust and Long-Lived Photochromic Textiles with Spiropyran Derivatives

Photochromic materials have attracted growing interest because they have the capability to undergo reversible color changes upon irradiation with light. The light fatigue resistance of photochromic materials and its affinity to biomass-based substrates are two important factors limiting applications. So, achieving robust and long-lived photochromic property for practical applications still remains a challenge. Herein, we report a silylation spiropyran and universal pad dyeing processes to attain smart photochromic textiles. Our approach consists of a silane substitution of spiropyran, thus acting as a coating to graft onto cotton fabrics under the action of the silane coupling agent. SEM, EDS, and XPS results of photochromic cotton fabrics showed that the silicon hydroxyl groups on the silanized spiropyran were strongly connected with –OH on the fabrics, which improved the affinity and binding fastness of spiropyran on the cotton fabrics. Importantly, our strategy tackles other severe problems encountered when dyeing photochromic molecules, such as difficult direct dyeing and low switching speeds in solid materials. This study is helpful in enriching the spiropyran derivatives, improving the affinity between photochromic compounds and fibers, and realizing the long-life application of photochromic fabrics. Moreover, it has great application prospects in hydroxyl-containing substrates, such as color-changing glass and anticounterfeiting paper, and potential application values in intelligent decoration and erasable information storage.