It’s an old idea: to paint without dyes, simply by sculpting the structure of a material on a nanometric scale. That’s how butterflies get such colorful wings. Chemists at the University of Florida have succeeded, for the first time, in making it credible.
Chemists from the University of Florida have just presented the first pots of “structural paints”: paints that are eco-friendly (no toxic dyes), economical (it takes 100 times less product to paint a surface) and eternal (it does not not discolor with age). Details from Hervé Poirier, editor-in-chief of the magazine Epsiloon.
franceinfo: Pots of paint of a new kind, pots of “structural paints”, what are they?
Herve Poirier: These small pots of blue, red, yellow, presented by physicists from the University of Florida, are impressive. Because, unlike conventional paints, they are dye-free paints. They do not contain pigments, which absorb specific wavelengths of light. In these new pots, the color comes from the very structure of the material. These are called “structural” paints.
That’s how butterflies get such colorful wings. Their colorless scales are actually sculpted into regular, tiny, nanoscale patterns that trap certain wavelengths. And the light that falls on it is reflected in a metallic blue, a blazing red, a luminous yellow. A whole host of techniques have been studied for decades in an attempt to imitate the butterfly – an emblematic case of biomimicry. And the cans of paint presented in Florida show that we are finally approaching industrial production.
How it works ?
It’s a bit technical, but basically in these paints, besides the binder, there is only aluminum and aluminum oxide, which have been skilfully bombarded with electrons to form nanostructures. Structures whose size can be adjusted so that the light reflects in the desired color. It is this same process that already makes it possible to produce the only structural paint produced industrially so far, “Lexus blue”, which the cars of this car manufacturer have proudly displayed for a few years. But today, the whole range of colors is concerned.
And why is it better than conventional paints?
These paints are more ecological: there are no more pigments, whose compounds are often toxic. They are also more economical: a surface can be covered with 400 times less material. They are more durable: they do not fade with age. They are also self-cooling: by reflecting the entire infrared spectrum, they allow a drop of 1 and 3°C compared to standard paint. And then, look at the butterflies: they are more lively! Well, this is still only laboratory work. But these cans of structural paint look set to hit DIY stores soon.