Highly Water‐Dispersible Spiropyran‐Octapeptide Supramolecules: Efficient, Multi‐processable, and Versatile Photoswitches for Time‐Dependent Dual‐Mode Encryption

AbstractWith exceptional photochromic and photoluminescent properties, spiropyrans have demonstrated significant potential for advanced information encryption and anti‐counterfeiting applications. However, its inherent water insolubility leads to incompatibility with aqueous polymers, and even more, its ease of leaching from the matrix hinders the formation of stable stimuli‐responsive platforms through direct blending with all polymers. Here, the fabrication of amphiphilic spiropyran‐octapeptide molecules is reported that can spontaneously self‐assemble into highly water‐dispersible supramolecular nanofibers in water. These assemblies exhibit universal polymer matrix compatibility while retaining the rapid photo‐responsiveness of spiropyrans. The formation of strong interactions between the supramolecular assembly and polymer chains ensures the long‐term stability of the resultant stimuli‐responsive materials in aqueous environments. These platforms fully preserve the base polymers’ processing properties, with silk fibroin as the matrix offering exceptional opportunities for constructing photo‐responsive platforms in various forms (e.g., films, gels, fibers, and coatings) with multiple functionalities using diverse solution processing techniques. Integrating distinct photochromic and photoluminescent responses within a single format without interference, combined with environmental stability and processing flexibility, enables the creation of dual‐mode, high‐security encryption devices for diverse application scenarios. The outlined strategy provides innovative concepts for developing high‐performance, versatile intelligent systems utilizing stimulus‐responsive molecules.