Waterproof organic-inorganic composite with fast reversible photochromic switch for UV indication and information storage

Design and preparation of photochromic materials with reversible color change under specific wavelength irradiation have been active research fields. However, these existing materials face a great challenge in rapid responsiveness and effective water management. Here, a waterproof composite with fast light response was successfully prepared by air-jet electrospinning and subsequent spray treatment. Specifically, its response time and saturation time are reduced to a few seconds and 1 min, respectively. Its reflectivity at 670 nm changes from 77.50% to 6.26%, which strongly indicates the large color contrast of this composite. Its natural fading process only takes 1 h, and infrared radiation can further reduce the erasure process to a few seconds. Concurrently, this material possesses hydrophobic properties and anti-adhesion performance, providing superior protection for its photochromism. Overall, this waterproof composite possesses rapid photochromism and appropriate spontaneous fading efficiency, enabling it to have a very broad application prospect in the fields of indicator materials, anti-counterfeiting materials, personalized labels, etc.