Why blue is one of the brightest colors in nature

From bird feathers to fruit skins, there are two main ways of displaying color in the natural world: through pigment substances that provide selective color absorption, or through structural color – subtle to control light reflection. Use of structures.

Now scientists have designed a computer model that suggests that the brightest matte structural colors in nature are always blue and green: because they are structural color boundaries within the visible spectrum of light.

We have a better understanding of how the brightest blues and greens are made in the natural world, research can also be important for developing vibrant, environmentally friendly paints and coatings that will not fade over time or contain toxic chemicals Will leave

“In addition to their intensity and fading resistance, a matte paint that uses structural paint will also be environmentally friendly, as toxic dyes and dyes will not be required,” says physicist Gianni Jacussi of the University of Cambridge in the UK. .

“However, we first need to understand what the limitations are for re-creating these types of colors before any commercial applications are possible.”

With structural color, the nanoscale framework on the surface determines the actual color.

Sometimes – as on peacock feathers, for example – that color may be iridescent, and there may be variations between color hues at different angles and in different lights. These are formed by ordered crystalline structures.

Peacock feathers are a classic example of structural color. (TJ Holowychuk / Unplash)

With other structures, you get a matte color that does not originate from cluttered structures; In nature it has been seen only in blue and green production. The emphasis of the new study was to see whether this was an inherent limitation of the said structures.

The new computer model, called photonic glass, is based on artificial materials, indicating that red is indeed beyond the scope of the scattering technique behind matte structural colors: easily reflecting the long-wavelength region of the visible spectrum These micro-surface structures cannot be used.

“Because of the complex interactions between single scattering and multiple scattering, and contributions from correlated scattering, we found that red, yellow and orange are rarely accessible,” says chemist Silvia Vignolini of the University of Cambridge.

Plum throated coating paintPlum-throated coatings exhibit vivid structural matte blues. (Redabbott / iNaturalist / CC-BY-NC)

This should be because bright matte red is produced using dyes in nature, rather than structural dyes. The team believes that the development in nature occurred due to different methods of producing red paint, as there are limitations to the underlying structures.

Knowing more about how these matte structural dyes are manufactured will take us closer to making pigments and dyes-free paints — an important step in long-lasting, environmentally friendly materials for many applications.

While this is still somehow off, and it looks like reds and oranges are going to need a different approach – other types of nanostructures might be able to work, having done more detailed research about them. After leaving, but for now materials scientists are having problems similar to the natural world.

“When we tried to artificially recreate the matte structural color for reds or oranges, we end up with a poor-quality result,” says chemist Lucas Schurtel of the University of Cambridge.

The research has been published in PNAS.


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