Researchers in Poland have developed a liquid that's super-light and flexible… until you shoot a bullet at it that is. Upon impact, their specially designed 'shear-thickening fluid', or STF, turns into a solid that's reportedly not just more comfortable than Kevlar - the most widely used material in bulletproof armour - but also offers even better protection against bullets and other projectiles.
Created by the Moratex Institute of Security Technologies, the liquid is what's known as a non-Newtonian fluid. Unlike regular Newtonian fluids like water, which only change their structure according to temperature or pressure fluctuations, non-Newtonian fluids change their viscosity under stress. In other words, they can quickly change from liquid to rock-hard solid when they're hit with something forceful, like a stray bullet, for example.
Right now, Kevlar bulletproof vests do a good job of blocking bullets, but the close-fitting material that saves your life can also warp inwards up to four centimetres upon impact, which can greatly injure, and even kill, the wearer, the deputy director of Moratex, Marcin Struszczyk, told Reuters.
"Thanks to the properties of the liquid, thanks to the proper formation of the insert, we eliminate one hundred percent of this threat because we have reduced the deflection from four centimetres to one centimetre," he added, referring to their new liquid.
The institute is being tight-lipped on what exactly their fluid is made of, but they revealed that when fitted in a vest, it's capable of stopping bullets fired at 450 metres (or 1,400 feet) per second.
And because such a large area of the liquid turns solid upon impact, it distributes the energy of the blow, which means that the bullets are less likely to ricochet, Reuters explained. This also means the wearer feels less impact.
"The point is for them not to interfere, not change the way of movement, operation of such the product by the user, and at the same time increase their motor skills, increase effectiveness of their decision process and increase their possibilities during the mission at hand," said Struszczyk.
But the Polish team isn't the only one turning gel-like substances into life-saving armour. Scientists in the UK announced in 2010 that they're testing a lighter bullet-proof material that combines Kevlar with an STF. And the US is developing a similar fluid that contains suspended ceramic nanoparticles, which hardens when hit or shaken.