Non-iridescent modulation of chiral structure of cellulose nanocrystals under molecular constraints

The chiral helical structure with adjustable structural color constructed by layered self-assembly of cellulose nanocrystals (CNC) is eye-catching. However, the highly-ordered periodic framework of traditional CNC chiral structure exhibits strong iridescent characteristics in macroscopic structural colors, severely limiting the development of CNC in non-iridescent fields. Herein, a novel method for constructing CNC chiral structure with non-iridescent properties by controlling the CNC assembly trajectory through molecular constraints of cationic polyacrylamide is innovatively proposed, successfully breaking the iridescent optical limitations of traditional CNC chiral structure. It is worth noting that, in combination with molecular docking technology, the important role of energy regulation in CNC self-assembly system for constructing CNC non-iridescent structures has been revealed for the first time. Interestingly, CPAM 1.5 % chiral film not only eliminates the angle dependent optical properties of traditional CNC chiral structure, but also exhibits efficient separation of circularly polarized light. In addition, based on its excellent non-iridescent properties and mechanical properties, CPAM chiral films have been further developed for applications in optical encoding encryption and solvent recognition. We believe that this work will open up new theoretical and application channels for the development of CNC chiral structure in non-iridescent optics.