Multi-level encryption of information in morphing hydrogels with patterned fluorescence. Issue 11 (25th February 2022)

• Record Type: Journal Article
• Authors: Hou, Li Xin; Ding, Hongyao; Hao, Xing Peng; Zhu, Chao Nan; Du, Miao; Wu, Zi Liang; Zheng, Qiang
• Is Part Of: Soft matter. Volume 18:Issue 11(2022)
• Page Start: 2149
• Page End: 2156
• Publication Date: 2022-02-25
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d2sm00083k
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We describe a strategy to improve information security by combining shape morphing and patterned fluorescence in a bilayer hydrogel. The information concealed in the hydrogel becomes readable after shape recovery and under UV light irradiation. Abstract : Fluorescent hydrogels have attracted tremendous attention recently in the field of information security due to the booming development of information technology. Along this line, it is highly desired to improve the security level of concealed information by the advancements of materials and encryption technologies. Here we report multi-level encryption of information in a bilayer hydrogel with shape-morphing ability and patterned fluorescence. This hydrogel is composed of a fluorescence layer containing chromophore units in the poly(acrylic acid) network and an active layer with UV-absorption agents in the poly( N -isopropylacrylamide- co -acrylic acid) network. The former layer exhibits tunable fluorescence tailored by UV light irradiation to induce unimer-to-dimer transformation of the chromophores, facilitating the write-in of information through photolithography. The latter layer is responsive to temperature, enabling morphing of the bilayer hydrogel. Therefore, the bilayer hydrogel encoded with patterned fluorescent patterns can deform into three-dimensional configurations at room temperature to conceal the information, which is readable only after successive procedures of shape recovery at an appropriate temperature and under UV light irradiation from the right direction. The combination of morphing materials and patterned fluorescence as a new avenue to improve the encryption level of information should merit the design of other smart materials with integrated functions for specific applications.