Liquid Armor — or, rather, armor made from a liquid that quickly turns solid on impact — is becoming a possibility:
A new “liquid armor” could be the solution for protecting the parts of the body that aren’t currently covered by standard-issue ballistic vests — arms and legs, where many of these devastating and life-threatening injuries occur. Co-developed by two research teams — one led by Norman Wagner at the University of Delaware, and the other led by Eric Wetzel at the U.S. Army Research Lab in Aberdeen, MD — the liquid technology will soon lead to light, flexible full-body armor.The liquid — called shear thickening fluid is actually a mixture of hard nanoparticles and nonevaporating liquid. It flows normally under low-energy conditions, but when agitated or hit with an impact it stiffens and behaves like a solid. This temporary stiffening occurs less than a millisecond after impact, and is caused by the nanoparticles forming tiny clusters inside the fluid. “The particles jam up forming a log jam structure that prevents things from penetrating through them,” Wagner explains.
Wagner and Wetzel developed a way to specially treat ballistic fabrics, such as Kevlar, with the liquid, making them dramatically more resistant to puncture and much better at reducing blunt trauma.
“We integrate those materials with the fabric itself, imbibe it in a way, such that the shear thickening fluid is not at all evident, it’s not a coating on the outside. It’s actually intercolated directly into the material,” says Wagner.
The stiffening of the liquid allows the energy of an impact to be distributed over a much larger surface area — so the force, rather than being focused on the area of a bullet head, is distributed over the area of the surrounding fabric. Ballistic tests have demonstrated that the treatment can actually prevent bullets from penetrating.
The treated Kevlar is even better at resisting puncture from sharp projectiles, such as knife stabs or shrapnel from roadside bombs. As Wagner explains, Kevlar was never designed to function against puncture.