Norman Wagner at the University of Delaware and Eric Wetzel at the US Army Research Lab in Aberdeen, MD, have invented a liquid armor that may 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.