Shark Skin, Butterfly Wings Inspire New High-Tech Surfaces

Taking advantage of the obvious may accelerate innovation much more than an attempt to reinvent the wheel. This just happened to researchers who found a way to tune surfaces in a very specific way to keep them from getting dirty and, if they are dirty, making them easier to clean.

Bharat Bhushan and Howard Winbigler at Ohio State University found that using the texture of shark skin, a rice leaf or a butterfly wing on a plastic surface enabled them to clean up to 98 percent of dust compared to only 70 percent off a regular flat surface. The discovery could be important for high-tech surfaces for aircraft and watercraft, pipelines, and medical equipment, the researchers said.

"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," Winbigler said. "And self-cleaning surfaces would be useful for medical equipment – catheters, or anything that might harbor bacteria."

The scientists used an electron microscope to reveal the texture of the Giant Blue Morpho butterfly wing. According to Bhushan, the surface resembled a "clapboard roof with rows of overlapping shingles radiating out from the butterfly’s body, suggesting that water and dirt roll off the wings like water off a roof." They also investigated the textures of rice leaves, fish scales, shark skin, and plain flat surfaces in respect to their ability to repel dirt and water.

To test how easy the surfaces are to clean, the researchers recorded the number of silicon carbide particles on each texture and then dripped water over the surfaces from a syringe for two minutes. Counting the silicon carbide particles after this process, they found that 98 percent of particles disappeared from the shark skin, 95 percent were removed from the rice leaf, 85 percent from the butterfly wing and only 70 percent from the flat surface.

*Image courtesy of What We Do Media.

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