"The material, a mix of liquid polymers and silica (tiny sandlike particles), is called shear thickening fluid. Left alone, it’s a free-flowing goo; when something hits it at high velocity, the bits cluster into a rigid barrier. After the force of impact dissipates, it reverts to a gel. Protective-gear maker Armor Holdings is integrating STF into bullet-proof vests. That means fewer layers of anti-ballistic fabric, making them lighter, more comfortable, and cheaper. The company aims to start selling to prisons later this year."
From Business Week Online:
"It seems crazy, Robert R. Schiller admits: the notion that you could shield yourself from bullets, shrapnel, and knives by donning the equivalent of a wet suit. But by early next year the president and chief operating officer of Armor Holdings Inc. (AH ) aims to be selling what he describes as "liquid armor" -- garments constructed from layers of tough fibers and fluid polymers -- to prison guards. By the end of 2007, he hopes, police and maybe soldiers will begin wearing the company's new protective gear as well. For the corrections market in particular, Schiller says, "it has the potential to be a breakthrough product."