Chelating Coordination Regulated Photochromic Electrospun Nanofibers for Waterproof and Long-Color-Retention Rewritable Wearables

Photochromic materials with rapid color-switching, long color retention times, and rewritability are crucial for meeting the requirements of future rewritable ink-free media. However, these requirements are challenging to satisfy simultaneously due to the inherent constraints among these features. Herein, a novel photochromic nanofiber nonwoven fabric was designed and constructed based on a conjugated organic–inorganic hybrid structure through electrospinning and hot-pressing techniques. The as-prepared fabric can change color in merely 5 s under UV irradiation and can reach saturation within 2 min. In addition, upon the introduction of a potent metal chelator, its color retention time exceeds 14 days under ambient conditions, significantly longer than that of most rewritable materials recently reported (several hours to 5 days). Moreover, the fabric exhibits high writing resolution and can be photoprinted and heat-erased for over 100 cycles while still retaining 96% of its initial reflectivity. Hydrophobic thermoplastic polyurethane provides the fabric with excellent waterproof and antifouling properties, thus preventing the composite from swelling or collecting graffiti due to moisture or dust. This work exploits a competitive approach for designing flexible, rewritable, and superior functional wearables with practical applications.