Bioinspired Dynamic Camouflage Skin Combining Structural Colors and Electrochromic Backgrounds

Many natural creatures have adaptive skin colors for mutual information exchange, camouflage, and protection. Inspired by the extraordinary color camouflage of living things, various artificial skins with tunable structural colors that rely primarily on temperature, pH, and mechanical stimuli have been reported. Some insects have the ability to camouflage by exhibiting or hiding their surface color on different backgrounds, such as Closterocerus coffeellae, whose wings appear transparent in front of a white background and iridescent on top of a dark background. In this work, a dynamic color film combining a photonic crystal hydrogel and an electrochromic hydrogel as the background color is prepared. Through voltage controlling, the color of the electrochromic hydrogel changes from a bleached state to a colored state, thus modulating light scattering and absorption, which enables the structural color of the PC hydrogel to disappear and appear. Furthermore, patterned structural color images can be precisely controlled to display or hide by electrical stimuli at low voltage. The electrically powered color-changing hydrogel system has potential applications in the fields of camouflage, display, and warning functions.