Reprogrammable Supramolecular Fluorescent Polymers for Rewritable Information Encryption and Anti‐Counterfeiting

Abstract The development of rewritable information encryption technology with high security is essential to meet the increasing confidentiality needs, however, it remains challenging. Hence, a strategy using self‐growth technology and host–guest interaction to construct reprogrammable photoswitchable supramolecular fluorescent polymers (PSFP) is developed, enabling rewritable information encryption. In this strategy, the polymerizable adamantane (AD) is integrated into polymer materials by employing the self‐growth method to create the desired 3D structure on the surface of the matrix. The fluorescent dyes modified by β ‐cyclodextrin (CDPA and CDNA) and photochromic spiropyran‐linked β ‐cyclodextrin (CDSP) are incorporated into the growing structure through host–guest interactions between AD unit and β ‐cyclodextrin ( β ‐CD) moieties. Based on the photo‐induced fluorescence resonance energy transfer (FRET) process, PSFP can undergo reversible dual‐state fluorescence switching between blue/green and red. Interestingly, owing to the dynamic features of host–guest interactions, the fluorescent information can be erased and rewritten easily. These outstanding performances promote to apply PSFP to rewritable information encryption and anti‐counterfeiting labels. Overall, this strategy opens up new prospects for smart photoswitchable fluorescent materials.