Photonic Cellulose Films with Vivid Structural Colors: Fabrication and Selectively Chemical Response

Recent advances in structural-color cellulose nanocrystal (CNC) materials have been made toward chemical sensing applications; however, such materials lack sufficient color chroma for naked-eye observation, and their selective recognition to given chemicals as well as the corresponding mechanism has rarely been reported. Here, a dopamine-infiltration and post-polymerization approach is proposed to construct vivid structural-color composite films. The chiral nematic structure of CNC enables the structural coloration, while the strong light absorption of the polymeric co-phase, polydopamine (PDA) enhances the color chroma and visibility. By controlling the PDA amount, the composite films can detect organic solvents quantitatively and selectively via visible color changes. From the viewpoint of the compatibility and similitude principle, notably, a critical solubility parameter distance (R-0) between PDA and active solvents is defined with a three-dimensional Hansen solubility sphere; this well constructs a rule for the sensing selectivity of the chemochromic composite films. The findings design of colorimetric sensors with specifically testing objects.

Automated summary

This study proposes a method for constructing vivid structural-color composite films using dopamine infiltration and post-polymerization. The composite films, which combine the structural coloration of cellulose nanocrystals (CNC) with the strong light absorption of polydopamine (PDA), can quantitatively and selectively detect organic solvents through visible color changes. The study also defines a three-dimensional Hansen solubility sphere to control the sensing selectivity.