Self-assembly of binary particles and application as structural colors

This paper presents a novel and facile approach to fabricate robust structural color directly through the self-assembly of soft colloidal polymer spheres by the aid of nanosilica at ambient pressure and temperature without complicated equipment. In this approach, soft colloidal polymer spheres are synthesized by emulsion polymerization and then blended with colloidal silica to obtain a nanocomposite dispersion. When this dispersion is loaded onto the surface of composite materials, the colloidal polymer spheres and silica beads can directly self-assemble into robust crystal films with vivid structural colors. Neither soft matrix nor post-treatment are needed. The bright colors could be obtained and tuned easily by adjusting the size of the polymer spheres without any dyes or pigments. Compared with traditional substrates such as glass and polypropylene, the reflectivity and the attachment strength were much higher because the surfaces of the composite materials are more rich in polar OH-groups, which may help the self-assembly and attachment strength.