Colors in pearls, bird feathers, butterfly wings and opals can arise not from pigments, but from the way light interacts with microscopic structures. This effect, known as structural color, has inspired a research team led by Professor Shu Yin of Tohoku University to develop a simpler production method in collaboration with researchers from several institutions in Japan, Taiwan and China, as well as Daito Kasei Kogyo Co., Ltd. The findings were published in Advanced Materials.
Many existing structural-color materials require microscopic structures to be arranged with great precision, making them complex and costly to manufacture. The new approach instead combines the irregular layered appearance associated with pearls with the light-absorbing properties found in bird feathers. Light reflects and interferes within the uneven layers, while absorbers increase the visibility of selected colors.
The researchers first created layered materials from cerium carbonate hydrate. Its thin, irregular layers reflect light in different directions and produce a soft, pearlescent white appearance through interactions between the reflected waves. They then applied light-absorbing compounds, including iron oxyhydroxide, to the surface. By varying the type and quantity of these materials, the team produced red, blue, purple and green colors.
Heat treatment improved the materials' stability by converting cerium carbonate hydrate into cerium oxide and iron oxyhydroxide into iron oxide. According to the research team, the materials retained their layered structure and pearlescent appearance after heating.
The researchers also examined possible uses by creating artwork and coatings, incorporating the materials into plastics and applying them to human skin as an exploration of their potential in cosmetics. Professor Yin said that developing a simpler way to create the colors was only a starting point and that future work would focus on their use in everyday applications.
The study, titled “Multi-Biomimetic Structural Colors Inspired by Pearls and Bird Feathers,” was authored by Zhiwei Wang and colleagues and published in Advanced Materials in 2026. Its DOI is 10.1002/adma.75074.
Sources: Phys.org.