Learning to harness the forces of nature

Learning from nature is the basis of all good science, but this is beginning to take on a more literal meaning. Mike Evamy discovers that the smart scientists are a bunch of potato heads.

The potato has always been dear to mankind. We have turned it into many things: mash, Smash, chips and, if we’re being fancy, au gratin. But it seems we are only just beginning to appreciate its properties. It seems incredible, but the humble potato holds secrets that could be replicated in new generations of aircraft, making them “smarter” and safer.

A team at the University of Reading has been studying the mechanical properties of the potato – what forces are at play beneath its skin. The potato has a cellular structure with a high internal pressure, which is exerted evenly across the entire internal surface of the skin. Scientists believe they can reproduce the effect to produce aerofoils that change shape from within, and which could replace the traditional flaps on aircraft wings.

The success of Reading’s project may hinge on the potato-chopping skills of its lead researcher. Speed is of the essence. When a potato is cut, its mechanical properties immediately start to alter, according to Dr Julian Vincent of Reading’s Centre for Biomimetics. “In order to get consistent results, the researcher found she had to reduce to a minimum the time it took to prepare a potato sample for the test machine. She got it down to about half a minute. The potato was, basically, responding to being cut,” he says.

Let us not forget, the potato is a living thing. And it is living things that hold the key to a wide range of emerging hi-tech products and systems, not to mention to improvements in existing ones, such as aircraft. Biomimetics is a branch of science that takes systems developed by plants and animals over millions of years and mimics them, to produce machines and advanced materials with revolutionary properties. It adapts the brilliant, fragile designs of nature for the purposes of humans. For designers, biomimetics promises a new wave of synthetic materials that imitate the good things of natural materials – low-energy manufacture, sensitivity and recyclability – and have applications from paper and packaging to computer components and aircraft.

Scientists are doing this with new technologies, right down to the scale of molecules. But mimicking nature is not a new idea. Records dating back 3000 years show Chinese sages attempting to produce artificial silk; even then the real stuff was a prized commodity. More recent design triumphs include the Eiffel Tower, which was inspired by studies of the way a hip bone transfers loads, and Velcro, whose inventor owned a dog that would come in after a run, covered in the seeds of Burdock plants. More recently, scientists have concentrated on developing replacement body parts, the silicon breast being the most obvious one.

And, if you count the efforts of Daedalus to equip his son Icarus with wings, then biomimetics has mythical roots. But we all know what happened to Icarus. According to Vincent, Daedalus’ mistake was to try to copy nature, rather than mimic it. “Working out how an animal or a plant does something is only half the story. If you can make your own versions, you can test your ideas in a much cleaner way because you can get rid of some of the confusing factors you find in the natural system, which is trying to do half a dozen other things that you’re not particularly interested in.

“For a long time, engineers looked at biological materials and said, ‘Well, they’re very interesting but basically they’re rubbish because they won’t withstand high temperatures.’ They didn’t understand the driving forces behind the evolution of biological materials, or that they are totally different to the driving forces behind the development of technological materials.”

This is why the field demands the collaboration of biologists and engineers: they seek out ways in which plants and animals have adapted to their environment, and then model these mechanisms artificially. Their database is the entire breadth of nature.

At present, the biggest push in biomimetics research is coming from the military. The US Navy is behind efforts at American universities and businesses to develop robust biomimetic robots based on crabs, fish, even flies.

It is easier to envisage spin-off consumer applications for biomimetics on projects where the formation and structure of natural materials are being understood. Molluscs, for example, produce their own composite materials in the form of seashells, whose growth could be mimicked in future to create medical implants, computer chips or body armour.

The flutter of butterfly wings is being studied by researchers at Tufts University in the US. They believe the microscopic scales the insect uses to regulate its temperature, could offer the microprocessor industry a model for controlling the heat dissipated from chips when they are fabricated and used. As chips become more powerful, they generate more heat – the Pentium II can shove out 40 watts – a problem the industry has to solve soon.

Car manufacturer Opel has been optimising the design of engine and chassis parts using software that imitates the way trees protect themselves by growing thicker at vulnerable points. At Reading’s Centre for Biomimetics, Vincent and Professor George Jeronimidis are studying the internal structure of antler bone, and what gives it its characteristic toughness, in order to drive the development of impact-resistant clothing from bulletproof vests to helmets.

The design of strain sensors in the skin, or cuticle, of insects such as locusts offers avenues for developing detectors in aircraft and buildings. The way the sea cucumber changes the stiffness of its body wall – by altering the interaction between its collagen fibres and the sugar polymer matrix it sits in – is, like the potato, the potential inspiration for shape-change materials. And the phenomenal insulating quality of penguin feathers is being examined to find new heatable building materials that could drastically reduce energy consumption.

Packaging is a huge drain on materials and energy, but biomimetics may hold some answers. The Reading Centre is currently developing a form of expanded starch – biodegradable, recyclable and cheap – as an alternative to moulded polystyrene. It seems to work as a cushioning material, and the next step is to modify it to enable the precision-moulding needed for the packaging of white goods and other big price-tag consumer durables.

Having initially encountered scepticism from the engineering community, biomimetics is now being accepted widely. “The engineering community is deciding more and more that natural systems offer very useful and interesting models,” says Vincent.

“Natural systems have evolved in competition with each other to be, more or less, minimum energy solutions to particular problems. If you can go to the engineers and say, ‘Look, you have something here that is optimised, uses less energy and will be a cheaper option’, they’re going to be interested,” says Vincent.

They should be, nature has had a lot longer than engineers to evolve strong, responsive, low-energy, recyclable materials. “Years ago, there was an article in Nature magazine on the evolution of motor cars. They used MG as an example, showing the way in which materials had controlled the energy consumption. In the early days, tyres were at least half the cost of keeping a vehicle on the road because they were so useless. Now it’s a fairly low fraction of the cost because of improvements in materials. So you can look at energy expenditure and say that evolution in both natural and technological systems is, to a large extent, based on materials,” says Vincent.

After all, Man’s own evolution is marked out in materials – the Bronze Age, the Iron Age. Scientists predict a new Age of Materials, but it will dawn slowly, almost imperceptibly. “You won’t notice it. We’ll just notice that things will get cheaper and use less energy while our standard of living improves. And, with a bit of luck, we won’t screw up our world so much,” says Vincent.

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