Self-cleaning Surfaces Take the Lotus Position
Photovoltaic cells and microelectromechanical systems have a problem: they collect dirt. What to do? Look to the lotus, says a EurekAlert article about research at Georgia Institute of Technology. Dr. C. P. Wong and team took inspiration from the self-cleaning surfaces of lotus leaves. “Despite growing in muddy conditions, the leaves and flowers remain clean because their surfaces are composed of micron- and nano-scale structures that –along with a waxy coating –prevent dirt and water from adhering,” the article says. “Despite their unusual surface properties, the rough surfaces allow photosynthesis to continue in the leaves.”
Rain just beads up when it hits these amazing leaves, and any dirt gets carried off with the water as it rolls off. How does it do this? “The plant’s ability to repel water and dirt results from an unusual combination of a superhydrophobic (water-repelling) surface and a combination of micron-scale hills and valleys and nanometer-scale waxy bumps that create rough surfaces that don’t give water or dirt a chance to adhere.”
It took awhile to find a material that could mimic these properties and also survive UV radiation in sunlight. They found a working prototype in “a combination of silicone, fluorocarbons, and inorganics such as titanium dioxide and silicon dioxide.” While lacking the self-regenerating properties of the lotus leaf, this surface mimics the structural properties that prevent water droplets from adhering. This could be a real boon for those large insulators on power poles that are difficult to clean, but can short out with dust accumulation. Another application could save your life some day. Lotus-imitative materials could be used by doctors to avoid clots from forming on prosthetic devices, such as stents. Even when rushing to the hospital in the rain, you may not need windshield wipers if you have lotus-like glass installed (see 01/18/2005 and 10/27/2004 entries).
Dr. Wong commented, “The lotus plant is yet another example of how researchers can learn surprising lessons from what Nature has provided.”
Articles like this typically fail to mention anything about evolution. This was no exception. One could argue that research like this is owned and operated, from conception to application, by intelligent design, inc.