Flexible and waterproof structural-color photonic composite films based on cellulose nanocrystals/poly(vinyl alcohol)/poly(ethylene glycol): fabrication and performance evaluation

Abstract

Most conventional anti-counterfeiting inks suffer from limitations such as monotonous security features, difficult identification by consumers and environmental pollution. In this study, we fabricated flexible and water-resistant cellulose nanocrystalline structured color composite photonic films by incorporating polyvinyl alcohol (PVA) and polyethylene glycol (PEG) into cellulose nanocrystal suspension. The resulting composite films are not only environmentally friendly, but also exhibit significantly different structural colors under different light sources and angles. The addition of PVA and PEG greatly improves the water resistance and flexibility of photonic films, addressing the issues of brittleness and poor water resistance in pure CNC films. Moreover, the crushed material retains its particulate architecture, chromatic characteristics, and responsive properties, which can be used to prepare photonic pigments with angle and light source dependence. This material demonstrates promising application potential in diverse fields such as anti-counterfeiting technologies, decoration and intelligent displays.