Dual-imaging-mode smart hydrogel information platform for illumination-independent covert decryption and read

Smart hydrogel with color responsiveness is envisioned as one of the most promising materials for advanced information encryption and decryption platform, but the illumination-dependent way of decrypting and reading information leads to the worrying of concealment in some particular scenarios. Herein, we proposed a smart hydrogel information platform with dual imaging modes by utilizing the accompanying behaviors in transparency change and heat releasing after crystallization of supercooled solution. For this smart hydrogel information platform, the hidden information could be written and decrypted by ink of ethylene glycol and decryption tool of seed crystal, respectively. Furthermore, in addition to the traditional optical imaging mode with the assistance of light illumination, the decrypted information on dual-imaging-mode hydrogel platform also could be read by thermal imaging mode in dark environment owing to the exothermic crystallization. The illumination-independent read mode based on heat radiation helps to improve the secrecy and safety of the decryption and read process. This investigation provides a facile and feasible strategy to design illumination-independent information platform that enables reading the encrypted information in secret.