Scientists find strongest natural material

A scanning electron microscope image of limpet teeth

Limpet teeth might be the strongest natural material known to man, a new study has found.

Researchers from the University of Portsmouth have discovered that limpets – small aquatic snail-like creatures with conical shells – have teeth with biological structures so strong they could be copied to make cars, boats and planes of the future.

The study examined the small-scale mechanical behaviour of teeth from limpets using atomic force microscopy, a method used to pull apart materials all the way down to the level of the atom.

Professor Asa Barber from the University’s School of Engineering led the study. He said: “Nature is a wonderful source of inspiration for structures that have excellent mechanical properties. All the things we observe around us, such as trees, the shells of sea creatures and the limpet teeth studied in this work, have evolved to be effective at what they do.

“Until now we thought that spider silk was the strongest biological material because of its super-strength and potential applications in everything from bullet-proof vests to computer electronics but now we have discovered that limpet teeth exhibit a strength that is potentially higher.”

Professor Barber found that the teeth contain a hard mineral known as goethite, which forms in the limpet as it grows.

He said: “Limpets need high strength teeth to rasp over rock surfaces and remove algae for feeding when the tide is in. We discovered that the fibres of goethite are just the right size to make up a resilient composite structure.

“This discovery means that the fibrous structures found in limpet teeth could be mimicked and used in high-performance engineering applications such as Formula 1 racing cars, the hulls of boats and aircraft structures.

“Engineers are always interested in making these structures stronger to improve their performance or lighter so they use less material.”

The research also discovered that limpet teeth are the same strength no matter what the size.

“Generally a big structure has lots of flaws and can break more easily than a smaller structure, which has fewer flaws and is stronger. The problem is that most structures have to be fairly big so they’re weaker than we would like. Limpet teeth break this rule as their strength is the same no matter what the size.”

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