Surface engineering toward self-cleaning and color-fastness photonic textiles

Structural coloration using photonic crystals (PCs) has emerged as a significant approach in the textile industry due to their environmental contributions. Cellulose nanocrystals (CNCs), crucial bio-PC with abundant resources and renewability, have shown great potential as photonic dyeing agents. However, due to the high water sensitivity, addressing the anti-washing performance and color fastness becomes important yet challenging. Here, we demonstrate a two-step approach for preparing superhydrophobic and iridescent cotton fabrics (SICFs). By co-assembling CNCs and poly (ethylene glycol) diacrylate under various sonication durations, flexible and tunable chiral nematic nanostructures are constructed on the cotton fabric surfaces. Additionally, surface superhydrophobicity and self-cleaning functions are imparted through the grafting of hyperbranched polyglycidol and 1H, 1H ' , 2H, 2H ' -perfluorodecyltrichlorosilane. Compared to hydrophilic structural-color counterparts, the resulting SICFs exhibit robust color fastness, surface anti-wettability, and water stability. The molecular design of this work provides new insights to development of eco-friendly textile industry.