Preparation and solar detection of photochromic fibers and fabrics with fast and reversible UV response

In this paper, a high-performance photochromic system with rapid fading was constructed by adjusting the pH of tungstate, introducing dopants, reducing agents and polydimethylsiloxane (PDMS) coatings. In addition, the chromaticity of photochromic materials can be precisely controlled by changing the doping and reducing agent content. Continuous large-scale fabrication of novel photochromic fiber/fabric using dip coating and wet spinning has been proposed. The photochromic fibers/fabric exhibit significant color contrast (ΔE = 40.2), rapid color switching (5 s), fast fading time (10 min), good cycling stability (20 times), as well as long color-retention (7 days) under UV/visible light irradiation. Photochromic fibers after packaging with PDMS have excellent water resistance and maintain good photochromic properties even after washing (20 cycles) when exposed to water, ethanol, and detergent solutions. The photochromic fibers can be used as wristbands or embroidered on various textiles as wearable UV indicators. With the increase of UV dose, it has real-time and sensitive color rendering, which provides early warning for high dose UV radiation. The color-changing mechanism of photochromic fabric has been studied. In addition, photochromic solution has fast UV response and fading ability, which can realize the application of rewritable ink, color-changing film. Notably, its preparation process has the advantages of low cost, environmental friendliness and large-scale production, providing a new solution for smart sensing and anti-counterfeiting application.