The Polymer Society of Korea

Abstract

We report a regioselective bottom-up assembly strategy for forming dual-colored photonic micropatterns using two distinct colloidal species. By exploiting differences in nucleation behavior and interaction strength, selective crystallization of each colloid is achieved within predefined regions, enabling spatially separated photonic grains with distinct structural colors. Controlled tuning of depletant and salt concentrations allows precise regulation of crystallization sequence and domain selectivity, resulting in well-defined color contrast within a single patterned area. The resulting micropatterns exhibit uniform grain orientation, yielding stable and vivid dual-color optical responses. This approach enables controlled color integration without sequential processing or physical confinement and provides a general route toward multi-component photonic micropatterns via bottom-up colloidal assembly.