|March 14, 2023||Volume 19 Issue 10|
Modern Applications News
Metalworking Ideas For
Today's Job Shops
Tooling and Production
Strategies for large
UCF-developed plasmonic paint uses a nanoscale structural arrangement of colorless materials (aluminum and aluminum oxide) instead of pigments to create colors. Here, the plasmonic paint is applied to the wings of metal butterflies, the insect that inspired the research. [Credit: UCF]
By Katrina Cabansay
Instead of pigment-based colored paint, which requires artificially synthesized molecules, a UCF researcher has developed an alternative way to produce colored paint that is more natural, environmentally friendly, and lightweight.
University of Central Florida (UCF) researcher Debashis Chanda, a professor in the school's NanoScience Technology Center, has drawn inspiration from butterflies to create the first environmentally friendly, large-scale, and multicolor alternative to pigment-based colorants, which can contribute to energy-saving efforts and help reduce global warming.
The development was published March 8, 2023, 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."
Based on such bio-inspirations, Chanda's research group innovated a plasmonic paint, which utilizes nanoscale structural arrangement of colorless materials -- aluminum and aluminum oxide -- instead of pigments to create colors.
While pigment colorants control light absorption based on the electronic property of the pigment material (and hence every color needs a new molecule), structural colorants control the way light is reflected, scattered, or absorbed based purely on the geometrical arrangement of nanostructures.
Such structural colors are environmentally friendly, as they only use metals and oxides, unlike present pigment-based colors that use artificially synthesized molecules.
Detail of the UCF-developed plasmonic paint applied to the wings of a metal butterfly. [Credit: UCF][
The researchers have combined their structural color flakes with a commercial binder to form long-lasting paints of all colors.
"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."
Additionally, because plasmonic paint reflects the entire infrared spectrum, less heat is absorbed by the paint, resulting in the underneath surface staying 25 to 30 degrees Fahrenheit cooler than it would if it were covered with standard commercial paint, the researcher says.
"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 lb of plasmonic paint could cover a Boeing 747, which normally requires more than 1,000 lb 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."
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.
For more information about licensing this technology, please visit the Inorganic Paint Pigment for Vivid Plasmonic Color technology sheet.
Published March 2023