Researchers have developed a new energy-saving paint that dissipates heat, comes in any color and should last for centuries. It is also the lightest paint ever made.
Inspired by butterfly wings, this paint is not made from pigments. Instead, color is created structurally through the arrangement of nanoparticles. The team calls it ‘plasmonic paint’.
Based on their calculations, it will only take 1.4 kilograms (3 pounds) Plasmonic paint to cover a Boeing 747 – you would need at least 454 kilograms (1,000 pounds) of conventional commercial paint to do this.
This means it can significantly reduce the amount of greenhouse gases required for flight.
To be clear, this paint has only been created in the lab, so we’re a long way from making it extensively
But the researchers have already developed paint in different colors using techniques that are easily scalable, and that’s what they’ll be working on next.
A big motivation for bringing this paint to market is that it can also help keep structures cool: the structure of the plasmonic paint reflects the entire infrared spectrum, so less heat is absorbed.
The Researchers say Surfaces under that new paint are 13 to 16 °C (25 to 30 °F) cooler than if they were covered with regular commercial paint.
“More than 10 percent of total electricity in the United States goes toward air conditioning,” says nanoscientist Debashis Chand from the University of Central Florida, who led the team that developed the paint.
“The promise of temperature difference plasmonic paint will lead to significant energy savings. Using less electricity for cooling will also reduce carbon dioxide emissions, reducing global warming.”
Currently, pigment-based paints require specific molecules to produce color, and typically, in modern paints, those pigments are synthetically synthesized.
The electronic properties of each molecule control how much light is absorbed and, therefore, what color the paint appears. That means there needs to be a new pigment for each new paint color.
Instead, plasmonic paint uses nanoparticles of two colorless substances – aluminum and aluminum oxide. By arranging them in different ways on top of an oxide-coated aluminum mirror, it is possible to control how light is scattered, reflected or absorbed.
A similar mechanism is responsible for the rich colors of butterfly wings.
“The range of colors and hues in the natural world (is) astounding – from colorful flowers, birds and butterflies to underwater creatures such as fish and cephalopods,” Chanda said.
“Structural coloration serves as the primary color-producing mechanism in several highly vibrant species where the geometric arrangement of two normally colorless substances produces all color. On the other hand, with (man-made) pigments, new molecules are required for each color present.”
The structural color is what makes the paint so light – at just 150 nanometers thick, the paint becomes fully pigmented, Lightest paint on record.
In this study, the team developed structural paint using a Electron beam evaporator which heats a substance at a very controlled rate.
This controlled evaporation allows small clusters of aluminum nanoparticles to self-assemble—the aluminum atoms are more attracted to each other than to the oxide substrate on which they grow, so they naturally agglomerate.
By changing the pressure and temperature of the electron beam evaporator, the team could create structures that reflect different colors.
“Importantly, this pressure- and temperature-controlled process ensures high reproducibility over a wide area in a single step, reducing production costs and enabling large-scale fabrication.” Groups write on their paper.
The researchers combined their structured paint flakes with a commercial binder, meaning the paint would last for hundreds of years — at least, in theory.
“Normal color fades because the pigment loses its ability to absorb photons,” Chanda said.
“Here, we’re not limited by that phenomenon. Once we paint something with structural color, it stays for centuries.”
It is not the first new type of paint to promise some incredible properties. Many of you will have heard of VantaBlack – one of the blackest paints in the world, capable of absorbing 99.96 percent of light.
Like plasmonic paint, this super blackness is the result of tiny carbon nanotubes, and even black paints are based on the same method.
There’s also ultra-white paint, which reflects 98.1 percent of all light and promises to significantly reduce the need for air conditioning. But unlike plasmonic paint, ultra-white paint relies on pigments to reflect light, and VantaBlack currently only comes in one color.
Still, there’s a long way to go before we can all customize our own plasmonic paint colors and use just one small can to paint an entire house.
“Traditional pigmented paint is made in large facilities where they can produce hundreds of gallons of paint.” Chanda said.
“At this point, until we go through the scale-up process, it’s still expensive to produce in an academic lab.”
The study was published Advances in science.