Researchers have created the "lightest paint in the world", but not in the way you might expect. While others battle for brighter and more reflective colors, this paint takes inspiration from nature to be incredibly lightweight, needing just a fraction of the normal amount of paint to cover the same area.
The new paint doesn’t create color in the traditional sense of using artificial pigments, but instead uses a mechanism similar to that of a butterfly, in which varying molecular structures create a stunning array of colors.
“The range of colors and hues in the natural world are astonishing — from colorful flowers, birds and butterflies to underwater creatures like fish and cephalopods,” said Debashis Chanda, a researcher at the University of Central Florida, in a statement.
“Structural color serves as the primary color-generating mechanism in several extremely vivid species where geometrical arrangement of typically two colorless materials produces all colors. On the other hand, with manmade pigment, new molecules are needed for every color present.”
Traditional paint uses either organic pigments or inorganic pigments, which each have their strengths and weaknesses. These artificial pigments are produced on a mass scale and can vary in price, but typically use metal oxides to create different colors and shades. The pigment is then mixed with solvents, binders, and resin to create a paint. The drawback is that each individual color needs a different material, making new color creation quite an arduous process.
Instead, researchers looked at how nature is able to produce dazzling colors without cramming in bucket-loads of pigment, and the result was a new, plasmonic paint. It uses colorless aluminum and aluminum oxide instead of pigment and the color comes from the geometric structures of the material, with light interacting differently with each structure to result in various displays. The structured flakes are then added to the rest of the paint materials to create a finished product.
According to the researchers, the process is more environmentally friendly as it cuts out the artificial pigment, but the wonders don’t stop there. As plasmonic materials reflect the entire infrared spectrum, the paint stays significantly cooler than standard paint, keeping surfaces cooler. While pigment is damaged by sunlight, this new paint stays bright for longer.
But perhaps the most interesting advantage is that the plasmonic paint needs a layer just 150 nanometres thick to be at full color, compared to current paints which recommend using around 9 mils.
Due to this, just a fraction of this paint is needed to cover a whole object – say, a Boeing 747 aircraft – compared to conventional paint, with just 1.3 kilograms (3 pounds) needed to cover the entire plane compared to 454 kilograms (1,000 pounds). This makes it the lightest paint in the world, Chanda said.
As with all new tech, the paint is currently very expensive to make, but Chanda wants to change that.
“The conventional pigment paint is made in big facilities where they can make hundreds of gallons of paint,” he said.
“At this moment, unless we go through the scale-up process, it is still expensive to produce at an academic lab.”
“We need to bring something different like, non-toxicity, cooling effect, ultralight weight, to the table that other conventional paints can’t.”
The research is published in Science Advances.