In my last column for The Biomimicry Manual, I mentioned the way the sea snake keeps herself clean of barnacles and algae by shedding her skin. Keeping surfaces clean is a huge challenge and a big industry. It’s a problem that comes up in nature all the time. Think about it: we have to dust to keep our home surfaces clean, but a plant can’t do that. But they need to let in maximum sunlight. They just can’t afford to be grungy! Lots of creatures deal with this same issue for all kinds of reasons. How do they do it? Can we learn better ways to stay clean from them? Read on to find out!
Cargo ship image via Shutterstock
Think about all the money and time we spend cleaning, not to mention all the water and toxic chemicals. Every two to three years, for instance, ships and boats of all sizes have to be hauled out of the water so owners can lather them in some 80,000 tons of copper-laden paints. It’s a necessary evil: it kills the algae and barnacles that make their home on boat hulls. Critters like these create drag, increasing fuel-costs by 40%. It’s a multi-billion dollar market. Boat-owners deplore the expense and loss of productivity, and harbor communities aren’t happy about their waters and sediments being poisoned. But with a global fleet of over 50,000 large ships burning 370 million tons a year of the worst-quality, highest-emission bunker fuel imaginable, it’s a damned-if-you-do-damned-if-you-don’t proposition. How would Mother Nature do it?
Great white shark image via Shutterstock
She provides us with lots of low-energy, non-toxic ideas for staying clean. Usually, she favors “structural” solutions over chemical or energetic ones. Take sharkskin, for instance. Most of the time, sharks cruise slowly, searching for prey. It’s a perfect ride for free-loading parasites. And yet, sharks stays clean. How? Tiny ridged scales, called “dermal denticles,” (literally, “skin teeth”) keep microorganisms from sticking. They are the inspiration behind ‘Sharklet,’ a thin sandpaper-like film, composed of millions of microscopic denticles. It’s a completely non-toxic, purely structural solution. Critters just don’t like to sleep on this unpleasant bed of nails. With it, boat hulls gather 85% less green algae, while hospitals using it on bathroom walls, door handles, and food trays avoid breeding antibiotic-resistant superbugs.
Floating coconut image via Shutterstock
The coconut provides a different solution. This giant seed is blanketed in a continuously shifting coat of microscopic hairs. Barnacles and algae just can’t get a purchase, allowing the seed to stay lightly bobbing in the waves until it safely floats to land. An effective surface based on this idea has been developed by the Biomimetics Innovation Center.
Tropical pitcher plant image via Shutterstock
The pitcher plant is renowned for its treacherous, slippery surface. It mimics delicious scents for its insect prey, which find themselves sliding headfirst into the pitcher, to be slowly (and presumably painfully) consumed. Slippery Liquid Infused Porous Surface (SLIPS) is a miracle film developed at Harvard University that mimics the pitcher’s spongy water-infused texture. Water- and oil-based liquids slide right off, like tiny doomed insect feet. Watch the video, it’s crazy stuff. Imagine using this on tools, work boots, and your car’s paint job.
Suitewall and Microguard are exterior wall and tile coatings that mimic the tiny bumps on a snail shell, using silica. The bumps attract microscopic drops of water for oily residues to “float” on. When rain hits the shell (or wall, or tile), dirt just washes away. This is the same trick used by the lotus. Over 100 patents have been filed using this idea, including Lotusan paint for buildings. Similarly, Morpho butterfly wings have a special nano-scale surface structure that repels water and dirt. NanoSphere® is a self-cleaning fabric finish that mimics this, reducing the need to do laundry (and for chemical detergents). If you have a pair of Levi’s 511 Skinny Commuter Jeans, you’re benefitting from this technology right now.
Can you think of applications for these kinds of ideas? I’m thinking we can use them to keep optical sensors and solar panels clean, repel the buildup of ice, rain, or snow on roads and aircraft wings, prevent blockage in pipes for oil or water flow, for biomedical devices, and even to stop graffiti. I’m sure you can think of a lot more. Like maybe never doing housework again. Thanks Nature.
An evolutionary biologist, writer, sustainability expert, and passionate biomimicry professional in the Biomimicry 3.8 BPro certification program, Dr. Tamsin Woolley-Barker blogs at BioInspired Ink and serves as Content Developer for the California Association of Museums‘ Green Museums Initiative. She is working on a book about organizational transformation inspired by nature.