Colors occur either as pigments that absorb certain colors while reflecting/scattering others or as structural coloration caused by microscopic structures. Many living things in the natural world produce this type of structural coloration that results in vivid colors, including morpho butterflies,
peacocks, and jewel beetles. Biomimetics is gaining attention as a field that utilizes the functions and structures of these living things in the development of new technology and manufacturing processes by mimicking them. In Application News No. A502, we confirmed the existence of tructural coloration on a multi-layered film produced by mimicking the wing structure of morpho butterflies, in which the coloration was caused by interference.1) The vivid colors observed on the wings of some birds are also structural coloration. For example, the structural coloration of peacock plumage is said to originate from the arrangement of
melanin granules.2) Michinari Kohri, Associate Professor at the Division of Applied Chemistry and Biotechnology at Chiba University's Graduate School of Engineering, has succeeded in producing highly visible structural coloration by controlling the size, blackness, refractive index, and arrangement of melanin-mimicking particles (PSt@PSA particles) created by coating the surface of polystyrene particles (PSt) with polydopamine (PDA), which is similar to melanin.3) This article introduces measurements of photonic materials with structural coloration performed in cooperation with Associate Professor Michinari Kohri.