Debashis Chanda, a professor at the University of Central Florida’s NanoScience Technology Center, was inspired by butterflies to develop the first environmentally sound, substantial, and multicolored replacement for pigment-based colorants, which can aid in energy-saving efforts and counteract global warming.
The development was published today in Science Advances as a featured article.
“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,” Chanda says. “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.”
Chanda’s research team invented a plasmonic paint based on such bio-inspirations that uses the nanoscale structural arrangement of colorless materials aluminum and aluminum oxide in place of pigments to generate colors.
In contrast to pigment colorants, which control light absorption based solely on the geometrical arrangement of nanostructures, structural colorants control how light is reflected, dispersed, or absorbed based solely on the electrical property of the pigment material.
The conventional pigment paint is made in big facilities where they can make hundreds of gallons of paint. At this moment, unless we go through the scale-up process, it is still expensive to produce at an academic lab.
Professor Debashis Chanda
As opposed to the current pigment-based colors, which use artificially manufactured molecules, such structural colors only use metals and oxides, making them environmentally neutral.
To create long-lasting paints in all colors, the researchers have coupled their structural color flakes with a commercial binder.
“Normal color fades because pigment loses its ability to absorb photons,” Chanda says. “Here, we’re not limited by that phenomenon. Once we paint something with structural color, it should stay for centuries.”
The beneath surface stays 25 to 30 degrees Fahrenheit cooler than it would if it were painted with regular commercial paint because plasmonic paint reflects the full infrared spectrum and thus absorbs less heat, the study claims.
“Over 10% of total electricity in the U.S. goes toward air conditioner usage,” Chanda says. “The temperature difference plasmonic paint promises would lead to significant energy savings. Using less electricity for cooling would also cut down carbon dioxide emissions, lessening global warming.”
Plasmonic paint is also extremely lightweight, the researcher says.
“This is due to the paint’s large area-to-thickness ratio, with full coloration achieved at a paint thickness of only 150 nanometers, making it the lightest paint in the world,” Chanda says.
The paint is so lightweight that only about 3 pounds of plasmonic paint could cover a Boeing 747, which normally requires more than 1,000 pounds of conventional paint, he says.
Chanda says his interest in structural color stems from the vibrancy of butterflies.
“As a kid, I always wanted to build a butterfly,” he says. “Color draws my interest.”
Future research
Chanda says the next steps of the project include further exploration of the paint’s energy-saving aspects to improve its viability as commercial paint.
“The conventional pigment paint is made in big facilities where they can make hundreds of gallons of paint,” he says. “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,” Chanda says.
