High optical contrast, dual-responsive, wearable photochromic fibers for smart textile engineering

Abstract

Smart textiles exhibiting responsiveness to external light stimuli show a great scope of applications in personalized decorations and intelligent wearable devices, among others. It's both rewarding and challenging to build wearable indicators based on fibers with high contrast and versatility to monitor the state of the external environment while maintaining good conformability and breathability for practical use. Here, we have integrated spiropyran photochromic compound (SP) into the spinning solution with polyvinyl alcohol (PVA) and aqueous polyurethane (WPU), and developed fibers by wet spinning featuring photochromic and photofluorescent dual outputs. Under UV and visible light illumination, the fibers demonstrate significant contrast optical signals, rapid color switching (4 s), long retention duration (7.5 h), as well as good cycling stability (20 times). The photochromic fibers can be used in the form of photochromic wristbands or embroidered on various textiles as flexible wearable UV indicators. Furthermore, the UV-induced fibers also produce pertinent color changes when subjected to acidic and alkaline vapors. We envision that the as-prepared fibers present promising applications in environmental acidity detection and multi-stimulus responsive materials.