Bio-inspired core–shell dyeing and derived patterned fluorescent tough hydrogels for multiple information encryption

Constructing advanced fluorescent anti-counterfeiting hydrogels is crucial for highly secure and powerful information encryption. However, lipophilic fluorescent molecules and accessible decryption condition make it challenging in fluorescent hydrogel fabrication and information validity. Herein, we draw an inspiration from the cellular mechanical response regulation to develop a universal swelling-deswelling strategy that embeds lipophilic fluorescent molecules into hydrophilic core–shell poly (stryrene-block-1-vinylpyrrolidone) (SP) and blocks most exogenous stimuli. Benefiting from reversible swelling behavior and rich hydrogen bond binding sites of SP, the proposed strategy could be expanded to multiple lipophilic dyes and prepared dyed SP is suitable for almost all hydrogels. Using lanthanide dyed SP as fluorescent units and dual network hydrogel as matrix, multiple anti-counterfeiting functions including nonvolatile, rewritable, and dual information storage and encryption, are realized by designing hydrogel architectures and regulating photo-responsive behaviors. It is believed that such research would inspire further studies on multifunctional hydrogel development for multi-level anti-counterfeiting and intelligent information encryption.