image: In the top of the figure can be seen different fluoresces are given different information (No emissive = 0, Red = 1, Green = 2), composed of different polymer blocks of 3D Code A upon different UV light and visible light exposure, such as the decryption method reported in the article, the system state gradually decrypted information "HNUST" (a, b, and c), due to the strong self-healing ability, 3D Code A can be quickly reconstructed to 3D Code B, similarly, it can also decrypt for new information "HUNAN" (d, e, and f). “The self-healable pixel units allowed for rapidly rearranging and assembling new encrypted information” Chen says. view more
Credit: ©Science China Press
This study is led by Jiang J (Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan University of Science and Technology; College of Chemistry and Key Laboratory of Polymeric Materials & Application Technology of Hunan Province, and Key Laboratory of Advanced Functional Polymeric Materials of College of Hunan Province, Xiangtan University), Prof. Dr. Cui J (Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China) and Prof. Dr. Chen J (Key Laboratory of Theoretical Organic Chemistry and Functional Molecule of Ministry of Education, Hunan University of Science and Technology).
Inspired by the fantastic ancient technique of "letterpress printing", they propose a new strategy for producing encrypted messages recyclable. This strategy is based on four kinds of self-healable photoswitchable fluorescent polymers (PFPs) with different fluorescence, P0, P1, P2, and P3. These polymers are composed of a PBA-co-PS backbone, self-healable 2-ureido-4[1H]-pyrimidinone (UPy) units, and two different photochromic fluorescent units (SDTE and BTBA). Intermolecular hydrogen-bonding interactions provided by the UPy units allow rapid reconfiguration of these polymers. In contrast, SDTE and BTBA provide green and red fluorescence when subjected to different light stimuli. Additionally, polymers P1 and P2 have similar dual-state fluorescence switching. Furthermore, because of the fluorescence resonance energy transfer of closed-ring SDTE to closed-ring BTBA under UV light, the emission of polymer P3 can be reversibly switched among red, green, and quenched states.
These polymers display rapid photoresponsiveness, high contrast fluorescence switching, outstanding long-term stability and thermostability, high fatigue resistance, excellent mechanical properties and rapid self-healing ability, and superior acid–base stability.
“Using these polymers to make pixel units allows us to construct recyclable multiple encrypted information. We envision that the idea of reconfigurable multiple encryption functions will emerge as a valuable complement to other optical encryption approaches targeting improved information security,” Chen says.
See the article:
Inspired by the fantastic old technology of “letterpress printing,” a novel strategy for reversibly making encrypted information is proposed.
https://doi.org/10.1007/s40843-022-2309-4
Journal
Science China Materials