The US Army Research Lab in collaboration with the University of Delaware developped a special liquid called shear thickening fluid. It is actually a mixture of hard nanoparticles and nonevaporating liquid. When fabric has been impregnated and struck by a knife or bullet, it immediately becomes rigid and prevents the object from penetrating. The rest of the time, the fabric is flexible and lightweight.
Red capes and tight pants will soon be provided for every American soldier.