Dual‐Encryption in a Shape‐Memory Hydrogel with Tunable Fluorescence and Reconfigurable Architecture

• Published in: Advanced materials (Weinheim) 2021-07, Vol.33 (29), p.e2102023-n/a
• Main Authors: Zhu, Chao Nan, Bai, Tianwen, Wang, Hu, Ling, Jun, Huang, Feihe, Hong, Wei, Zheng, Qiang, Wu, Zi Liang
• Format: Article
• Language: English
• Subjects: Aqueous environments; Chromophores; Configurations; Design; Dimers; Displays; Encryption; Fluorescence; Hydrogels; Hydrogen bonds; information encryption; Light irradiation; Mechanical properties; Methacrylic acid; Morphing; origami/kirigami; Photolithography; Reconfiguration; Shape memory; Smart materials; Stiffness; tough hydrogels; Ultraviolet radiation
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202102023

Materials capable of shape‐morphing and/or fluorescence imaging have practical significances in the fields of anti‐counterfeiting, information display, and information protection. However, it's challenging to realize these functions in hydrogels due to the poor mechanical properties and lack of tunable fluorescence. A tough hydrogel with good shape‐memory ability and phototunable fluorescence is reported here, which affords reprogrammable shape designing and information encoding for dual‐encryption. This hydrogel is prepared by incorporating donor–acceptor chromophore units into a poly(1‐vinylimidazole‐co‐methacrylic acid) network, in which the dense intra‐ and interchain hydrogen bonds lead to desirable features including high stiffness, high toughness, and temperature‐mediated shape‐memory property. Additionally, the hydrogel shows photomediated tunable fluorescence through a unimer‐to‐dimer transformation of the chromophores. By combining photolithography and origami/kirigami designs, hydrogel sheets encoded with fluorescent patterns can deform into specific 3D configurations. The geometrically encrypted fluorescent information in the architected hydrogels is readable only after sequential shape recovery and UV light irradiation. As demonstrated by proof‐of‐concept experiments, both the fluorescent pattern and the 3D configuration are reprogrammable, facilitating repeated information protection and display. The design of tough hydrogels with rewritable fluorescent patterns and reconfigurable shapes should guide the future development of smart materials with improved security and wider applications in aqueous environments. Reprogrammable dual‐encryption of information storage is realized in a tough hydrogel with good shape‐memory ability and phototunable fluorescence, enabling reconfigured 3D architectures and rewritable 2D fluorescent patterns, respectively. The encrypted information in the architectured hydrogel becomes readable only after sequential shape recovery and UV light irradiation, affording improved security and reuse of information materials in aqueous environments.