Direct fabrication of template-free beads-on-a-string three-dimensional structural color yarn

The application of dye-free bionic materials in imparting distinctive structural colors to textiles has received increasing attention in recent years. Herein, inspired by the structure of normal pearl-necklaces, a novel beads-on-a-string yarn manifesting vivid structural colors was directly fabricated without the assistance of a template. Drawing from the relatively-controlled Stöber method, silica (SiO 2 ) nanoparticles of a certain size and spherical shape were initially produced to build the foundation for constructing specific photonic crystals that generate designated structural colors. A thermal-assisted vertical deposition approach was then used build a beads-on-a-string structure on the substrate yarn which has brilliant structural colors because the colloidal nanoparticles undergo self-assembly and the substrate yarn detached from fabrics acquires a specific curvature after weaving the original fabrics. To improve the mechanical robustness of beads-on-a-string three dimensional (3D) structural color yarns, a protective and transparent coating poly(methyl methacrylate-butyl acrylate) (PMB) was synthesized and then spray-coated onto the as-prepared beads-on-a-string structural color yarn. This work provides new insight for fabrication of structural-colored yarns with particular beads-on-a-string structures and bright 3D structural colors, showing great potentials of developing a new 3D structural-colored yarns in diverse textile coloration areas.