Scalable Structural Coloration of Carbon Nanotube Fibers via a Facile Silica Photonic Crystal Self-Assembly Strategy.

The coloration of carbon nanotube (CNT) fibers (CNTFs) is a long-lasting challenge because of the intrinsic black color and chemically inert surfaces of CNTs, which cannot satisfy the aesthetic and fashion requirements and thus significantly restrict their performance in many cutting-edge fields. Recently, a structural coloration method of CNTFs was developed by our group using atomic layer deposition (ALD) technology. However, the ALD-based structural coloration method of CNTFs is expensive, time-consuming, and not suitable for the large-scale production of colorful CNTFs. Herein, we developed a very simple and scalable liquid-phase method to realize the structural coloration of CNTFs. A SiO 2 /ethanol dispersion containing SiO 2 nanospheres with controllable sizes was synthesized. The SiO 2 nanospheres could self-assemble into photonic crystal layers on the surface of CNTFs and exhibited brilliant colors. The colors of SiO 2 nanoparticle-coated CNTFs could be easily changed by tuning the sizes of SiO 2 nanospheres. This method provides a simple, effective, and promising way for the large-scale production of colorful CNTFs.