Programming structural-colour modulation range of elastomer enables information storage

Cholesteric liquid crystal elastomers (CLCEs) has garnered significant attention in the field of information display and storage. Obtaining multiple structural colours in a single elastomer film is highly desirable but presents a considerable challenge. Here, we have successfully achieved manipulable range of structural colours in a CLCE film by ingeniously introducing the photopolymerisation during thiol-acrylate reaction process. This particular strategy involves triggering spatial shrinkage of the polymer network in a pre-designed region following solvent evaporation, resulting in a blue shift of the structural colour compared to the background. Consequently, we can construct multi-colour and multi-pattern elastomer films by precisely controlling the localised polymerisation. Notably, these patterns can be concealed in a reversible manner as the film undergoes a specific degree of elongation and can be restored when external force is removed. This work demonstrates a straightforward method of programming structural-colour modulation range, eliminating the need for material changes or intricate preparation processes, broadening the applications of stretchable elastomers in information storage, encryption, anti-counterfeiting, and dynamic photonics.