Multi-stimulus response AIE fluorescent hydrogel for "Blind box" multistage secure information encryption

Aggregation-induced emission (AIE) hydrogels have been widely applied in the field of information security due to their tunable optical properties and aggregation-induced emission properties. The introduction of spiropyranoid organic fluorescent dyes with multi-stimulus response into AIE hydrogels will endow them more functions. However, the traditional 2D anti-counterfeiting has the problem that the hidden information is easy to be copied. Therefore, it is urgent to develop a new anti-counterfeiting strategy to improve the level of information security. In this study, we present for the first time a new strategy of combining multi-stimulus response AIE fluorescent hydrogels with shape memory polyurethane to apply them in the field of information security. The polymer skeleton of fluorescent hydrogel (PCHS hydrogel) is composed of polyvinyl alcohol (PVA) and carboxymethyl chitosan (CMCS) through hydrogen bonding. Four [4-(3, 5-dicarboxyphenyl)] tetraphenyl ethylene (H8ETTB) and 1- (2-hydroxyethyl) -3, 3-dimethylindolin-6 '-nitrobenzo spiropyrone (SP) are chosen as the fluorescent fillers. PCHS hydrogel is printed onto shape memory polyurethanes (SMPU) by a flexible electronic printer. As a result, the hidden information printed on the SMPU needs to be decrypted at temperatures (80 degrees C) and under ultraviolet irradiation(365 nm). Moreover, the hidden information can be destroyed by adding H+ or applying external force after heating to 80 degrees C. This effectively improves the security of the information and prevents its disclosure. Interestingly, we can choose the destruction method to make the destruction of information more flexible. This strategy has great potential in the field of information encryption and anti-counterfeiting.