Cellulose nanocrystal (CNC), as a potential green iridescent coating, is restricted by being susceptible to interference of chiroptical properties by substrate effects or shearing effects. In this work, polystyrene, glass, ceramic, wood, stainless steel, and metal or metal alloy were supplied as substrates for preparing cast coating or shear coatings. Furthermore, structural color, interface interaction, initial solid content and processing velocity or temperature were evaluated for fabricating sustainable iridescent CNC coatings on variable substrates. Results show that the structure color of acidic CNC were easily disturbed by metal or metal alloy with poor acid corrosion resistance or high water-absorbency ceramic or rapid interface shearing in scaled-up industrial processing. Interface interaction and potential destruction mechanism for the coatings were also discussed in detail. Practically, several optional efficient solutions are proposed, i.e., increasing the initial solid content of CNC, enhancing water-retention of substrates, raising processing temperature, or slowing down shearing velocity. Hence, we provided a strategy of fabricating environmental-friendly, iridescent, stable, and industrially scalable coatings of CNC.

cellulose nanocrystal, coating, structure color, substrate, processing