Bright structural color films independent of background prepared by the dip-coating of biomimetic melanin-like particles having polydopamine shell layers

Some beautiful structural colorations found in nature are produced by microstructures of melanin. Polydopamine (PDA), produced by the self-oxidative polymerization of dopamine, is known as a mimetic material of melanin. Previous experiments by our group have shown that PDA-based structural color materials produced bright structural colors upon enhancing the color saturation through the absorption of light scattering. Herein, we describe the preparation of structural color films by a dip-coating of biomimetic melanin-like particles with PDA shell layers. Various parameters of the dip-coating method influencing the structural coloration were investigated in detail. Experimental results revealed that the obtained films exhibited bright and angle-dependent structural colors independent of a background color, i.e., black or white background. These findings provide new insights for the development of dye-free ink technologies. (C) 2017 Elsevier B.V. All rights reserved.