Lower critical solution temperature

Information leakage

Engineering

Polymer chemistry

Materials science

Computer security

Encryption

Computer science

Chemical engineering

Polymer

Camouflage

Nanotechnology

Self-healing hydrogels

Copolymer

Artificial intelligence

Composite material

Upper critical solution temperature

Angewandte Chemie International Edition

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.

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