# A Simple Coloration of Calcium Alginate Fiber via Structural Colors

## TL;DR

Researchers developed a new way to color seaweed fibers using structural colors instead of traditional dyes.

## Contribution

A novel method to create vibrant structural colors on seaweed fibers using SiO2 nanospheres and polydopamine.

## Key findings

- Photonic crystals with rainbow hues were successfully applied to stain seaweed fibers.
- The color of the crystals depends on the size of SiO2 microspheres and can be tuned with dopamine hydrochloride ratios.

## Abstract

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.