A flexible, protective fabric tiled like crocodile skin can resist stabbing, cuts and abrasion. It could be used as armour in dangerous industrial and work settings or to make long-lasting shoes.
Materials designed to be resistant to mechanical damage, like puncture wounds or stabs, are often rigid and heavy because of the dense fibres used to make them hard to pierce. This can make it difficult to create practical armour or clothing from them.
Now, at the National University of Singapore and his colleagues have developed a material that resembles the scales of a crocodile by moulding tough tiles of modified epoxy resin on top of a polyester skin.
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To do this, they treated the polyester with a water and oil-proof liquid to make it bond better to the epoxy resin blocks, put it in a crocodile-skin shaped mould, and fused it using high pressure and a temperature of about 120掳C (248掳F).
When the researchers tested the fabric by attempting to cut it with a razor, they found that it was only slightly less resistant to cutting than stainless steel chain mail, even though it was a third as dense.
They also stabbed the fabric with a hypodermic needle, to mimic accidental slippage in medical situations.聽It was more resistant than a common titanium alloy used in the aerospace industry, withstanding a stabbing force of up to 38 newtons while the alloy聽normally manages聽just over 30 newtons.
And when the researchers stabbed a needle into the material as it was resting on someone鈥檚 arm, the person remained unscathed.
The material also performed well in tests involving rubbing abrasive substances against it, which could make it useful for making footwear, bags and packs and outdoor equipment, say the researchers.
The crocodile-like design of the textile is unique, says at the University of Leeds, UK, and the combination of its protective properties and lightweight nature is rare. However, the polyester skin is a potential weak link in the design and could allow very thin, sharp objects through between the scales. 鈥淵ou have a gap for all these structures,鈥� says Mao. 鈥淚f you get into this part of the material, it will fail.鈥�
This didn鈥檛 seem to happen with the hypodermic needles, though.
The way in which the different materials are fused together to create the skin-like texture could also make the material difficult to recycle, says Mao.
Advanced Functional Materials
