Pressure/Temperature Dual‐Responsive Cellulose Nanocrystal Hydrogels for On‐Demand Schemochrome Patterning

Abstract

Cellulose nanocrystal (CNC) based optical devices with adjustable schemochrome have attracted immense interest. However, most of the previously reported structural colored CNC‐based materials can only achieve simple stress‐induced color change, which have difficulty achieving multimode control of complex patterning that can be accurately identified. Here, inspired by the nanostructure‐based color‐changing mechanism of neon tetra, this study presents a pressure/temperature dual‐responsive CNC‐based schemochrome hydrogel with adjustable dynamic chiral nematic structure. By incorporating abundant interfacial noncovalent interactions, dynamic correlations between adjustable helical pitch of the vertically stacked cholesteric liquid crystalline (LC) phase and responsiveness of flexible thermosensitive substrate are established, which further enable wide‐range optical characteristic (12°–213° in HSV color model and 421–734 nm in the UV–Vis spectra) and identifiable visualized patterning. The resultant hydrogels are applied in proof‐of‐concept demonstrations of on‐demand schemochrome patterning, including customizable patterned dual‐encryption label, smart digital display, temperature monitor, and intelligent recognition/control system. This study envisages that the bioinspired construction of structural colored nanomaterials will have promising applications in smart responsive photonic equipment including smart display, anticounterfeiting, and intelligent control systems.