A Simple Coloration of Calcium Alginate Fiber via Structural Colors

Seaweed fiber is a new type of functional fiber made from natural seaweed as raw material. Seaweed fiber has excellent moisture absorption, bio compatibilization, controlled degradation profile, and flame retardancy, and can be used to develop high-performance and high value-added textiles. However, seaweed fibers are prone to swelling in salt ion solutions, making dyeing with traditional chemical dyes very difficult. In recent years, the research and application of controllable structural colors have been an important direction and hot spot in the textile field. SiO₂ nanospheres of different sizes were synthesized and combined with polydopamine as an additive to produce structural colors with high visibility. The resulting photonic crystals exhibited vibrant rainbow hues and were successfully applied to stain seaweed fibers. The color of polydopamine-coated silica photonic crystals (PDA/SiO₂) depended on the diameter of the SiO₂ microspheres, while their spectral purity could be tuned by adjusting the ratio of SiO₂ microspheres to dopamine hydrochloride.