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From the June 2009 Conservationist

A spider web with dew drops on it

Inspired by Nature

By Deborah J. Knight


I love sunny summer mornings. They beckon me to head out to the garden, coffee cup in hand, to soak in the peacefulness of the surrounding nature. Whether it's a spider web bejeweled with beads of morning dew, a butterfly fluttering by, or a long-awaited lotus flower blooming on the backyard pond's surface, mother nature never fails to delight me.

Aside from the beauty of these seemingly ordinary sights, there's a lot to be learned from what we observe. In fact, if you look closely, nature can provide creative and innovative solutions for making life safer, simpler, and healthier for both us and the environment.

Bulletproof vest
Spider silk is five times stronger than the
fiber used in bulletproof vests. (Photo:
James Clayton)

Take that spider web, for example. Spider web "silk" is five times stronger than Kevlar®, the artificial fiber currently used in bulletproof vests. Haven't you ever wondered how something as delicate-looking as a spider web, can capture fairly large, fast-moving insects? It's because spider silk can absorb five times the impact force of an insect hitting it, without breaking. Spider silk is incredibly elastic-it will stretch 40 percent longer than its original length and then bounce back. When compared to the man-made fabric nylon, spider silk is 30 percent more flexible.

With this in mind, scientists are studying how they can translate this natural wonder into a practical use to benefit mankind. Take Kevlar® for example. Kevlar® is a petroleum-based fiber whose manufacturing process requires high energy inputs and produces toxic by-products which can pollute our environment. In fact, our fiber industry is heavily dependent on petroleum, a diminishing resource. Scientists are conducting experiments to determine whether they can replicate the biological process a spider uses to build its web to create a similar fiber to make such products as parachutes, bulletproof fabrics, cables for suspension bridges, artificial ligaments, and sutures. This process of imitating or taking inspiration from nature's models to solve human problems is called biomimicry.

Janine Benyus, a biologist and author of the book Biomimicry: Innovation Inspired by Nature, is a national leader in promoting the biomimicry movement to science and industry. She says we shouldn't look at what we can extract from nature, but what we can learn from it. After 3.8 billion years of evolution, nature has "learned" what works, what is appropriate, what lasts, and what survives. She further explains that nature is a model of efficiency, where virtually nothing is wasted, and where natural systems work in harmony with each other, in communities. One species cannot occupy a place on our planet that uses up all of its resources to support its own expansion at the expense of the destruction of other communities, says Benyus. "Look around you! What you see are nature's success stories...the failures are the fossils."

Close-up of a lotus leaf with water droplets
Lotus leaf (Photo: Michael Steden)

Looking closely at the lotus flower in my backyard, I marvel at its design. It's not just the beauty of the flower that astounds, but that such beauty can originate from a plant that thrives on being rooted in the bottom of pond muck. The flower and the leaves look so clean, so
sparkling. In fact, have you ever noticed that after a rain, everything seems so refreshed and clean? How is it that leaves look so fresh-who is dusting Mother Nature's plants?

Microscopic view of the surface of a lotus leaf shows tiny bumps
Tiny bumps on the lotus leaf surface help
water roll off. (Photo: William Thielicke)

As it turns out, some scientists have been studying the lotus's self-cleaning mechanism and discovered that the seemingly smooth surface of the lotus leaf, at the nanoscale level, is actually made up of many bumps. These bumps are what make the leaf water-repellent-water simply rolls along the surface, taking bacteria and soil off in the process. This model of nature's self-cleaning, dubbed the "lotus effect," has already been the inspiration for new products. For example, a paint called Lotusan® was developed in 1999 for use on building exteriors. Like the lotus leaf, the paint contains microscopic bumps that induce raindrops to roll off, wetting the dirt and rolling it off the building's painted surface. Cleaner surfaces means less use of cleansers and water, and less need to repaint.

The lotus effect has also inspired the development of a product called GreenShield™, a fabric finish that creates water- and stain-repellency on textiles. This biomimicry-inspired product has resulted in a decrease in the use of environmentally harmful fluorocarbons, which is the conventional way of ensuring repellency in fabrics. General Electric global research scientists in Niskayuna, New York are also studying the lotus effect to manufacture nano-treated surfaces that will repel water from titanium slabs to allow turbines and engines to operate more efficiently.

Butterfly wings are another of nature's inspirations. Research has shown that the color found in butterfly wings is the result of two different things: the physical make up of the wings (i.e. nanostructures on the scales), and the wings' color pigmentation. The iridescence, reflectivity and optical features of butterfly wings may hold the key to figuring out improvements in LED lighting, anti-reflective coatings, brighter screens for cell phones and even chemical-free anti-counterfeiting technology.

Two cockleburs stuck to fabric
The tiny hooks on the cocklebur were the
inspiration for Velcro. (Photo: James
Clayton)

Many products we use, or will use in the future, are derived from biomimicry-inspired research and adaptation. Velcro®, for instance, was inspired by the tiny hooks on the cocklebur. Remember how annoying it was to get burs tangled in your hair when you were a kid and how much it hurt when your mother tried to comb those stubborn burs out? Well, Velcro® is the result of taking nature's form and translating it into human function.

In the Namib Desert, one of the hottest places on the earth and where water is scarce, there is an insect species that serves as a source of inspiration. The Namibian beetle has an ingenious way to fulfill its need for water in this harsh climate. Mist contained in periodic fog-laden winds settles on the beetle's back, which is covered with tiny bumps. Like on the lotus leaf, these bumps facilitate the formation of water droplets, which then slide down the beetle's body in "waxy troughs" to the insect's mouth. In a water-thirsty world, scientists are researching the potential to develop a fog-catching device that mimics this water-harvesting technique to get water in arid areas.

In Zimbabwe, Africa, the architectural design of the Eastgate Centre, a mid-rise office complex, was inspired by the structural qualities of termite mounds found in the desert. These mounds can maintain a constant temperature and humidity despite the extreme temperature variations found outside the mound. This is accomplished via the perpetual opening and closing of a series of heating and cooling vents throughout the mound over the course of the day. The termites constantly dig new vents and plug up old ones, circulating the air which is sucked in at the lower part of the mound, and then flows down into enclosures with muddy walls, and up through a channel to the peak of the termite mound. Using this model, the Eastgate Centre's ventilation system operates in a similar way. Outside air is drawn in and then either warmed or cooled by the building's mass, depending on which is hotter, the building concrete or the air. Fresh air steadily replaces stale air that rises and ultimately exits the building through chimneys. Eastgate Centre uses less than 10% of the energy of a conventional building its size-both an environmental and an economic win.

Another biomimicry-based innovation that has been a plus for green building is the development of new types of bio-based glues. These glues were developed by a scientist interested in the adhesive qualities of mussels attached to ocean rocks. Bio-based glues are non-toxic alternatives to conventional chemical-based glues, and are used as adhesives in construction materials such as particle board. This is a plus for those consumers who are allergic to the chemicals found in traditional glues. The use of bio-based glues can also reduce the amount of hazardous waste that occurs at the end of the product life cycle of these construction materials.

In a world with growing energy concerns, scientists again look to nature for inspiration, with sunlight as a focus. Solar technology is a perfect example of biomimicry in action, and scientists have been working for years to fully replicate photosynthesis-a very efficient process that plants use to convert light energy into chemical energy. At Rensselear Polytechnic Institute in Troy, for example, the Baruch '60 Center for Biochemical Solar Energy Research was recently created to develop the next generation of solar technology. Research at the center will include using plant photosynthesis as a biometric model to point the way to developing solar cell systems which can convert light into useable, more efficient energy sources.

Ultimately, biomimcry has the potential to help humans change their world into a more sustainable one-a world more harmonious with nature's systems. To quote Janine Benyus, "Nature runs on sunlight, uses only the energy it needs, fits form to function, recycles everything, rewards cooperation, banks on diversity, demands local expertise, curbs excesses from within, and taps the power of limits." It gives looking around your backyard a whole new meaning.

Deborah J. Knight is an environmental specialist with DEC's Pollution Prevention Unit in Albany.

Photo: Susan L. Shafer