Learning Lessons From Nature

744px-Bur_Macro_BlackBgBiomimicry or biomimetics is big business these days. Borrowing ideas from nature has obvious applications in the world of robotics (see our blog “Machines that mimic nature”) but the concept goes far wider than that: today, the natural world informs the design of everything from phone displays to medical devices and architecture to fasteners.

Popularised by scientist and author Janine Benyus in her 1997 book Biomimicry: Innovation Inspired by Nature, biomimicry endeavours to pursue a sustainable approach and takes its inspiration from nature as a “model, measure and mentor”. Here are five cool ideas that technology has borrowed from nature.

1          Velcro
Number one has obviously got to be Velcro, simply because of the ubiquitous nature of this material. As the first commercially marketed fabric hook and loop fastener, Velcro is derived from two French words velours (meaning “velvet”) and crochet (meaning “hook”). The material was invented in 1948 by the Swiss electrical engineer George de Mestral, who patented it in 1955, and subsequently refined the concept until its commercial introduction in the late 1950s.

So, how did de Mestrel get the idea for his invention? Velcro was conceived in 1941. The story goes that de Mestrel was out hunting with his dog. He was struck by the way in which burrs adhered to his clothing and dog’s fur so tenaciously, and took the opportunity to investigate the structure of the burdock seed heads to see what made them so “sticky’. Examining them under a microscope, he noted their hundreds of “hooks” that caught on anything with a loop, such as clothing, animal fur or hair.

It took de Mestrel many years to perfect a usable version and to hone the manufacturing process. Originally, it was poorly received by the fashion industry. However, the fabric received its first big break when it was adopted by the aerospace industry: it offered astronauts an easy way to manoeuvre in and out of bulky space suits. (This lead to an urban myth that Velcro was actually invented by NASA.) Interest from skiers and other sports followed and then the kids clothing industry. After that the success of Velcro was assured.

Larger hook and eye fastenings had been in use for centuries but the key to Velcro’s success was to follow nature’s model and miniaturise them.

2          Special coatings Drop_on_carpet
Carnivorous pitcher plants work by luring and then trapping bugs in a vat of water laced with digestive juices. The sides of the pitcher may have downward pointing hairs and be super smooth to prevent their meal from climbing back out. Scientists have used the slick leaves of the Nepenthes pitcher plant as the inspiration behind a non-stick coating. Applications range from self-cleaning surfaces that minimise the need for chemical cleaners to coating the inside of pipes to reduce clogging and lining sauce bottles so you can squeeze out the last drop of ketchup (minimising food waste).

A plant is also the inspiration behind a special waterproof coating. Salvinia molesta has eggbeater-shaped hairs that trap air and keep the plant floating on the surface of water. The shape of the hairs is what’s important, enabling them to trap air; what’s more, the tips of the hairs are sticky so they can cling to water. This arrangement creates a combination of buoyancy and adhesion to keep the plant floating but stable on water surface. Having recreated the material in plastic, scientists think it could be used on boats and marine vehicles.

3          Solar cells

If there’s one industry that owes its existence to biomimicry it’s the solar energy business. One example is an artificial leaf designed to generate power for off-grid homes in developing areas.

Scientists claimed a breakthrough in 2011 when they developed a prototype of a relatively cheap fuel cell that could be scaled up for manufacture.

The hope is that a single “leaf” can provide enough energy for an entire household. About the size of a poker card, this advanced solar cell works differently from typical photovoltaics, which convert sunlight into energy directly. Instead, the process uses water in a typical fuel cell process. Made from silicon, electronics and catalysts, the solar cell is placed in a gallon of water in bright sunlight where it can go to work splitting water into hydrogen and oxygen and storing the gasses in a fuel cell. The new leaf uses cheaper materials – nickel and cobalt – which reduces the manufacturing cost.

The “leaf” is made of inexpensive materials that are widely available, it works under simple conditions and is highly stable. Under lab conditions, the prototype artificial leaf was able to operate continuously for at least 45 hours without a drop in activity.

"A practical artificial leaf has been one of the Holy Grails of science for decades," said MIT’s Dr Daniel Nocera, who led the research team. “We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station. One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology.”

4          Electronic displays Morpho_didius_Male_Dos_MHNT

Think of the magical colours in soap bubbles. You get the same effect in nature with the colour of some insects’ wings. The brilliant blue colour of Morpho butterfly wings is the result of microstructures – ridges, cross-ribs, ridge-lamellae and microribs – that create the colouring effect, rather than being derived from pigmentation. Incident light waves are reflected at specific wavelengths to create vibrant colours generated by multilayer interference, diffraction, thin film interference, and scattering properties.

Scientists have been able to replicate the photonic microstructure of butterfly wings through biomorphic mineralization replicated using metal oxides or metal alkoxides. The technology has been used to create low-power-consumption displays, for instance for mobile phones, most notably by Qualcomm since 2007. It uses interferometric modulation to reflect light so only the desired colour is visible in each individual pixel of a display.

 

5          Biomimicry in buildings Icd_itke_pavilion5.jpg.492x0_q85_crop-smart

Biomimicry is all the rage in architecture. For instance, architects have looked to natural structures like termite mounds – which incorporate their own “air-conditioning systems” – to inform energy-efficient ventilation systems in buildings. Buildings can also mimic natural structures in their construction: for instance, this bionic dome designed by University of Stuttgart’s Institute for Computational Design and the Institute of Building Structures and Structural Design is built out of modular plywood sections modelled on the principles of a sea urchin’s plate skeleton.

The natural world can also provide inspiration for new building materials. For instance, a mollusc called the blue mussel creates its own glue to anchor itself to rocks that works under ambient temperature and pressure conditions and in a very wet and rough environment – the ocean! A manufactured version of this glue is now used in bonding wood-based construction products.

Nature can also help us protect the natural world. Millions of birds are killed each year by flying into the reflective glass of homes and office buildings. One approach is to attach stickers mimicking the silhouettes of raptors to warn small birds away from the glass. Another has been inspired by the fact that birds seem to be experts at avoiding flying into spider’s webs. It turns out that the webs reflect UV light that birds can see; this prevents our feathered friends from crashing into a web and destroying it. One manufacturer has reported 76% fewer bird collisions in field trials after incorporating this principle into its glass.

1 Comment

  • Biomimicry or biomimetics is big business these days. Borrowing ideas from nature has obvious applications in the world of robotics.

    Abbas Scientific Reply

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