A 3D multistage information encryption platform with self-erasure function based on a synergistically shape-deformable and AIE fluorescence-tunable hydrogel.

The traditional stored information is statically shown on single 2D planes, which leads to low information storage capacity and secondary information leakage without the proper handling of decrypted information. Developing a 3D multistage information encryption platform with self-erasure function is highly desirable. Here, a novel bilayer hydrogel with synergistic deformation and fluorescence color (SDFC) change is designed for 3D multistage information encryption. The bilayer hydrogel consisting of a shape-deformable hydrogel layer and a fluorescence hydrogel layer with aggregation-induced emission (AIE) properties can exhibit pH-responsive SDFC change. Fluorescence information can be ionoprinted on the fluorescent hydrogel layer based on electrostatic interactions and dynamic covalent bonds. The 2D bilayer hydrogel encoded with information can synergistically produce predesigned 3D shape configuration and enhanced background fluorescence to wrap information, which is only readable after sequential shape recovery with the disappearance of background fluorescence. Furthermore, multistage information can be further obtained by stepwise decryption due to information with differential fluorescence fading rates. The displayed information is automatically self-erased in the end, avoiding the information secondary leakage. This study paves an avenue for broadening conventional 2D single-level information encryption platforms to 3D multistage counterparts with self-erasure and multi-decryption capabilities based on SDFC change of the bilayer hydrogel.