NCJ Number
210081
Journal
Law and Order Volume: 53 Issue: 5 Dated: May 2005 Pages: 22,24,26
Date Published
May 2005
Length
3 pages
Annotation
This article describes new materials that have been and are being developed for applications in the law enforcement field.
Abstract
The U.S. Army is working on a materials application called "liquid armor," which involves combining a "shear thickening fluid" (STF) with Kevlar to improve wearability and effectiveness. The liquid component of STF is polyethylene glycol, which is nontoxic and stable over a wide range of temperatures. Hard nanoparticle of silica (glass) are suspended in the STF, and the mixture is soaked into the conventional Kevlar layers. Although flexible under the normal activity of the wearer, when struck with a projectile, the STF becomes a rigid barrier that resists penetration. After stopping the projectile, the STF returns to its customary flexibility. Liquid armor is far more stab resistant than conventional Kevlar, resisting even the force of an icepick stab. Another liquid application is liquid metal. This is an alloy unlike any other metal. Liquidmetal, the product developed by Liquidmetal Technologies, has an amorphous ("without shape") structure that resembles metal in its liquid phase. Liquidmetal retains this amorphous structure as it cools to room temperature and below, making the material more adaptable than conventional metals. Zirconium-based and titanium-based Liquidmetal has over twice the yield strength (amount of stress necessary to deform a material) of stainless steel and titanium alloy and almost three times the elastic limit. The material also has superior resistance to corrosion and wear. Applications in the public safety market include guns with Liquidmetal surfaces, which would be far more resistant to rust, corrosion, and wear. Another new material development underway involves carbon nanotubes, which are structures of 60 carbon atoms that are extremely strong and stable, with a tensile strength unlike any material yet produced, making it a candidate for improved body armor.