Solvent-Programmable ZnS Colloidal Coatings for Large-Area and Durable Structural Colors

Fade-resistant coloration based on the structural color of colloidal nanoparticles offers a promising alternative to conventional colorants. However, such ordered nanostructures suffer from two critical limitations inherent mechanical fragility and the difficulty of achieving precise patterning without complex surface modifications. To address these issues, we develop a robust strategy based on zinc sulfide (ZnS)/epoxy resin (EP) composites and rod-coating process. By spatially modulating the coating composition using customized filter-paper templates and localized solvent evaporation driven by capillary forces, we successfully program the refractive-index contrast, which strongly influences color expression according to the Bragg principle and enables on-demand patterning of structural colors. This localized solvent evaporation programming (LSEP) approach allows for the high-precision fabrication of complex dual-color patterns with excellent stability against abrasion, pH changes, and temperature variations. The proposed method is straightforward, environmentally friendly, and overcomes the limitations of traditional techniques, thereby opening new avenues for the scalable production of customized patterned structural color materials in displays, anti-counterfeiting, packaging, and decorative applications.