2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
A group of researchers from the United States, China and Belgium has developed a technology for producing particles of different colors using a combination of two materials - a particle core made of artificial melanin and a top layer of silicon dioxide. When such particles combine into large clusters, they form a photonic crystal. By adjusting the ratio of materials in the particle, the researchers learned how to obtain the desired color. The research is published in the journal Science Advances.
It is known that in nature, not all organisms are colored with pigments of certain colors. Some of them, for example many insects, use structural coloration. It is based on the formation of photonic crystals in which the optical properties change with a period comparable to the wavelength. Researchers have learned how to reproduce such structures, but existing technologies are too complex for practical use.
The authors of the new work have found another way to produce structural pigments. To do this, they used almost black artificial melanin and silicon dioxide. The researchers combined them into single particles with a melanin core and a silica surface. But since such particles themselves do not yet produce bright and adjustable colors, the scientists placed them in water, to which they then added an organic solvent.
After mixing the resulting liquid, the water broke into separate drops with particles in them. As a result, the density of the particles increased and they were organized into supramolecular complexes. Due to this structure, the complexes acquired a color, and its color depended on the ratio of the sizes of the melanin core and the dioxide surface.
The authors of the work note that the technology they have developed is quite simple, and the paints obtained with its help are stable and biocompatible, so that they can be used in tasks of the widest range.
Recently, Chinese scientists have created a structure-colored hydrogel with self-healing properties. The color of the final material can be changed in accordance with the same principle - by selecting structural elements of a certain size in the process of its creation.