Scalable Structural\nColoration of Carbon Nanotube\nFibers via a Facile Silica Photonic Crystal Self-Assembly Strategy

The coloration of carbon nanotube (CNT) fibers (CNTFs)\nis a long-lasting\nchallenge because of the intrinsic black color and chemically inert\nsurfaces of CNTs, which cannot satisfy the aesthetic and fashion requirements\nand thus significantly restrict their performance in many cutting-edge\nfields. Recently, a structural coloration method of CNTFs was developed\nby our group using atomic layer deposition (ALD) technology. However,\nthe ALD-based structural coloration method of CNTFs is expensive,\ntime-consuming, and not suitable for the large-scale production of\ncolorful CNTFs. Herein, we developed a very simple and scalable liquid-phase\nmethod to realize the structural coloration of CNTFs. A SiO2/ethanol dispersion containing SiO2 nanospheres with controllable\nsizes was synthesized. The SiO2 nanospheres could self-assemble\ninto photonic crystal layers on the surface of CNTFs and exhibited\nbrilliant colors. The colors of SiO2 nanoparticle-coated\nCNTFs could be easily changed by tuning the sizes of SiO2 nanospheres. This method provides a simple, effective, and promising\nway for the large-scale production of colorful CNTFs.