▷ 제목:  Structural Coloration with Curved Microscturcutres

▷ 내용: Structural coloration typically relies on periodic nanostructures at sub-wavelength scales, which has limited its practical applications due to the complexity of fabrication processes, even in bottom-up approaches. In this work, we introduce nanostructure-free curved microstructures that leverage total internal reflection and optical interference to generate structural colors. These microstructures include micro-crescents and microdomes. Micro-crescents are created by emulsifying a polymer-oil mixture dissolved in a co-solvent into water. As the solvent evaporates, phase separation between the polymer and oil leads to the formation of paired droplets. By removing the oil component, the resulting micro-crescents exhibit pronounced structural colors under directional light while remaining transparent under ambient conditions, making them ideal for anti-counterfeiting applications. Microdome arrays are fabricated through thermal reflow of micropillars made from a positive photoresist via photolithography. These microdomes, arranged in a predefined pattern, enable the creation of color images with precise graphics and adjustable brightness. Furthermore, by controlling the diameter of the micropillars during the reflow process while maintaining a constant height, the curvature of the microdomes can be tuned, allowing for the production of multicolor graphics in a single reflow step.