Fabrication of angle-independent anti-reflective structural color coating powders

Abstract

Structural color materials have attracted extensive attention due to their fadeless color, low toxicity and environmentally friendly features, but the colors based on photonic crystal structures are usually angle-dependent on incident lights. In this research, we have fabricated a powder material with three-dimensional ordered macropores (3DOM) structure of silica (SiO2) by a scarified template method. The micron-sized 3DOM SiO2 powders can diffract lights in certain wavelengths and exhibits vivid structural colors. The structural colors from the 3DOM SiO2 powder follows the Bragg diffraction of incident light on (111) stacked planes of the face-centered cubic colloidal crystals and the (111) crystal planes are randomly oriented. As a collective effect in the aggregation of micron-sized powders, the structural colors are angle-independent, and thus the 3DOM powders can be use as anti-reflective color coating material. In addition, because its diffraction can limit transmission and absorption of lights in some extent, so this 3DOM SiO2 powder can be also used as protective coating material for reducing light radiations.