SAN FRANCISCO—Researchers at Ohio State University are taking a new look at butterfly wings and rice leaves with an eye toward mimicking their texture to create more sterile high-tech surfaces for things like aircraft and watercraft, pipelines and medical equipment.
As an example, the researchers were able to clean up to 85 percent of dust off a coated plastic surface that mimicked the texture of a butterfly wing, compared to only 70 percent off a flat surface.
In a recent issue of the journal Soft Matter, the Ohio State engineers report that the textures enhance fluid flow and prevent surfaces from getting dirty.
"Nature has evolved many surfaces that are self-cleaning or reduce drag," said Bharat Bhushan, a professor of mechanical engineering at Ohio State. "Reduced drag is desirable for industry, whether you’re trying to move a few drops of blood through a nano-channel or millions of gallons of crude oil through a pipeline. And self-cleaning surfaces would be useful for medical equipment – catheters, or anything that might harbor bacteria."
Bhushan and doctoral student Gregory Bixler used an electron microscope and an optical profiler to study wings of the Giant Blue Morpho butterfly and leaves of the rice plant Oriza sativa. They cast plastic replicas of both microscopic textures, and compared their ability to repel dirt and water to replicas of fish scales, shark skin and plain flat surfaces.
The Blue Morpho, common to Central and South America, is an iconic butterfly, prized for its brilliant blue color and iridescence. It also has the ability to cast off dirt and water with a flutter of its wings.
For a butterfly, staying clean is a critical issue, Bhushan said. "Their wings are so delicate that getting dirt or moisture on them makes it hard to fly," he said.