Double Lock Label Based on Thermosensitive Polymer Hydrogels for Information Camouflage and Multilevel Encryption

• Published in: Angewandte Chemie International Edition Vol. 61; no. 16; pp. e202117066 - n/a
• Main Authors: Lou, Dongyang, Sun, Yujing, Li, Jian, Zheng, Yuanyuan, Zhou, Zhipeng, Yang, Jing, Pan, Chuxuan, Zheng, Zhikun, Chen, Xudong, Liu, Wei
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11.04.2022
• Edition: International ed. in English
• Subjects: Anti-Counterfeiting; Camouflage; Copolymerization; Encryption; Hydrogel; Hydrogels; Phase transitions; Polymers; Stimuli-Responsive Materials; Transition temperature; Transition temperatures; Stimuli-Responsive Materials; Encryption; Hydrogel; Polymers; Anti-Counterfeiting
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202117066

Developing extra safety encryption technologies to prevent information leakage and combat fakes is in high demand but is challenging. Herein, we propose a “double lock” strategy based on both lower critical solution temperature (LCST) and upper critical solution temperature (UCST) polymer hydrogels for information camouflage and multilevel encryption. Two types of hydrogels were synthesized by the method of random copolymerization. The number of −CO−NH2 groups in the network structure of the hydrogels changed the enthalpic or entropic thermo‐responsive hydrogels, and ultimately precisely controlled their phase transition temperature. The crosslink density of the polymer hydrogels governs the diffusion kinetics, resulting in a difference in the time for their color change. The combination of multiple LCST and UCST hydrogels in one label realized information encryption and dynamic information identification in the dimensions of both time and temperature. This work is highly interesting for the fields of information encryption, anti‐counterfeiting, and smart responsive materials. A double lock encryption strategy with both temperature and time as keys and excellent comprehensive capabilities has been established via a combination of lower critical and upper critical solution temperature (LCST and UCST) thermosensitive polymer hydrogels, of which the phase transition temperature and time can be arbitrarily tailored by changing the contents of monomer and crosslinker in their networks. This strategy provides powerful double insurances for confidential information.