Facile Access to High Solid Content Monodispersed Microspheres via Dual‐Component Surfactants Regulation toward High‐Performance Colloidal Photonic Crystals

Monodispersed microspheres play a major role in optical science and engineering, providing ideal building blocks for structural color materials. However, the method toward high solid content (HSC) monodispersed microspheres has remained a key hurdle. Herein, a facile access to harvest monodispersed microspheres based on the emulsion polymerization mechanism is demonstrated, where anionic and nonionic surfactants are employed to achieve the electrostatic and steric dual‐stabilization balance in a synergistic manner. Monodispersed poly(styrene‐butyl acrylate‐methacrylic acid) colloidal latex with 55 wt% HSC is achieved, which shows an enhanced self‐assembly efficiency of 280% compared with the low solid content (10 wt%) latex. In addition, Ag‐coated colloidal photonic crystal (Ag@CPC) coating with near‐zero refractive index is achieved, presenting the characteristics of metamaterials. And an 11‐fold photoluminescence emission enhancement of CdSe@ZnS quantum dots is realized by the Ag@CPC metamaterial coating. Taking advantage of high assembly efficiency, easily large‐scale film‐forming of the 55 wt% HSC microspheres latex, robust Ag@CPC metamaterial coatings could be easily produced for passive cooling. The coating demonstrates excellent thermal insulation performance with theoretical cooling power of 30.4 W m−2, providing practical significance for scalable CPC architecture coatings in passive cooling.