Multi-stimuli responsive hydrogels with shape memory and self-healing properties for information encryption

With stimuli-responsive fluorescence and similar structure to extracellular matrix, smart fluorescent hydrogels are good candidate to encode data, especially in drug and food anti-counterfeiting. However, the development of these hydrogels in multistage information protection to achieve higher data security level is limited. Herein, multifunction smart fluorescent hydrogels were constructed and utilized to develop different multistage data encryption platforms. The hydrogels are a new type of fully physically cross-linked gelatin/metal complex associated poly(acrylamide-acrylate) double network gel. They displayed Fe3+ and H+-responsive fluorescence quenching, temperature or Fe3+-induced shape memory and self-healing properties. Combining the above abilities, several multistage data encryption platforms, from 2D to 3D data encryption, were designed. The results demonstrated a bright prospect for this smart fluorescent hydrogel in high security level anti-counterfeiting applications.