Excellent optical, flexible, and mechanical properties of chiral cellulose nanocrystal films for structural coloration and fluorescent anti-counterfeiting applications

Cellulose nanocrystal (CNC)-based chiral nematic films have recently received attention due to their unique photophysical properties. However, their fragility and single structural color mode (birefringence) restricts their further development. Herein, a flexible optoelectronic, chiral, CNC films was reported composed of carbon quantum dots (CQDs) and CNCs produced by evaporation-induced self-assembly (EISA). Due to weak interactions between CQDs and CNCs, which limit molecular sliding, the optimal tensile strength and curvature reached 65.5 MPa and 2 × 102, respectively. In addition, these products retained not only the structural color of cellulose chiral films in the birefringent mode, but also introduced fluorescence in the CQD ultraviolet excitation mode. Related work also addressed the issue of cellulosic chiral film fragility and provided a new method for their production.