Water on knautia scabiosa: the surface is superhydrophobic and the drops are almost spherical
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Researchers from the University of Oxford and Nottingham Trent University are working together to understand the ways that plants and insects repel water to keep clean, dry, breathe underwater or float.
"Nature has a number of ways to deal with raindrops, from microscopic bumps and hairs on plants, to tiny ratchets on insects’ bodies," says Professor Julia Yeomans from Oxford University’s Physics Department. "By understanding how water moves on these surfaces, we can create materials that mimic the strongly water-repellent features, such as self-drying fabrics and stay-clean paint."
Plants, such as lupin and nasturtium, use bumpy waxed surfaces or microscopic hairs to repel water so that raindrops remain spherical and roll quickly over the leaves. Water spiders use hairs on their bodies to trap air to breathe, and water striders skip across the pond on hairy, water-repellent legs. Ratchets on butterfly wings help to direct raindrops away from the insect’s body.
The researchers are using mathematics and computer-modelling to investigate how drops move over the tiny bumps. They have been able to fabricate similar micropatterned surfaces, and are performing experiments to check the theories and to explore applications.
"Ideas from nature are helping us design surfaces to control water movement," says Julia. "The technology has great potential, from aviation to fashion."
Nature's Raincoats would like to acknowledge the sponsorship and support from:
The Engineering and Physical Sciences Research Council (EPSRC), a member of Research Councils UK, the strategic partnership of the seven UK Research Councils.
Nottingham Trent University
St. Hilda's College, University of Oxford
Materials Knowledge Transfer Network (Materials KTN)
Professor Glen McHale, Dr Michael Newton and Dr Neil Shirtcliffe, Nottingham Trent University
Professor Julia Yeomans, Dr Bortolo Mognetti, Dr Jorn Dunkel, Matthew Blow, Richard Matthews, Victor Putz, Ioannis Zacharoudiou and Irwin Zaid, University of Oxford