Scietists develop material that bounces bullets
By Roger Highfield, Science Editor

Last Updated: 12:01am GMT 31/10/2007

Security guards, police officers and armed forces could become Robocops able to take bullets in their stride, thanks to a carbon nanotechnology yarn which can defect projectiles without a trace of damage.

  A police officer wearing a bullet-proof jacket
Conventional bullet-proof jackets spread the bullet’s force

Conventional bullet-proof jackets, body armour and explosion-proof blankets consist of multiple layers of Kevlar, Twaron or Dyneema fibres which stop bullets from penetrating by spreading the bullet’s force.

But the people who use them can still be left with severe bruising or, worse, damage to critical organs.

The new material, however, not only stops bullets but deflects them, rather than absorbing their force.

The study by engineers at the Centre for Advanced Materials Technology, University of Sydney, is published in the Institute of Physics’ journal Nanotechnology.

The elasticity of carbon nanotubes means that this so called “blunt force trauma” may be avoided, say Prof Liangchi Zhang and Dr Kausala Mylvaganam.

“By investigating the force-repelling properties of carbon nanotubes and concluding on an optimum design, we may produce far more effective bulletproof materials,” the pair said.

Thanks to the properties of the new nanomaterials, “a bullet can be repelled with minimum or no damage to the wearer of a bullet proof vest”.

The team tested carbon nanotubes down to 0.7 nanometres (billionth of a metres) across, and a length of about 7.5 nanometres, by bombarding them with diamond bullets travelling at speeds varying between 1000 and 3500 metres per second, revealing the conditions when the bullet could bounce back, as the nanotube released energy stored during the initial impact.

Based on their findings, they calculate that six layers of woven nanotube yarn – about 600 millionths of a metre thick – may protect the wearer from a revolver bullet, so that it bounces off.

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