Liquid Body Armor

Photo courtesy U.S. Army. Photo by U.S. Army Sgt. Lorie Jewell U.S. Army Staff Sgt. Raul Lopez models a conceptual version of an Army Soldier's uniform in the year 2025.

With advances in weaponry, armies need to develop better body armor. Right now, scientists are working on a new breed of armor called "liquid body armor."

One type of liquid body armor is magnetorheological (MR) fluids. Scientists at MIT are working on a particular MR fluid. It is made up of small iron particles suspended in silicon oil. The oil prevents the particles from rusting. The fluid transforms from liquid to solid in just milliseconds when a magnetic field or electrical current is applied to it. The current causes the iron particles to lock in and stack on top of each other. This creates an amazing impenetrable shield. How hard the substance becomes depends on the strength of the magnetic field or electrical current. Once the charge or magnetic field is removed, the particles unlock, and the substance goes back to a fluid state. Scientists say that it will take five to 10 years to make this substance fully bullet resistant.

Researchers at the University of Delaware are working on another type of liquid body armor. Shear thickening fluid (STF) is also capable of transforming from liquid to solid in just milliseconds. But, instead of an electrical charge causing the change, heavy stress -- like the impact of a bullet or knife -- does the job. As soon as the stress is removed, the STF goes back to a liquid state. STF is made up of super small, hard particles of silica and liquid polyethylene glycol. The tiny particles are suspended in the liquid. Tests indicate that soaking KEVLARŪ fabric in STF markedly improves the capabilities of KEVLARŪ. The STF soaks into the fabric. The tight weave of KEVLARŪ holds the STF securely in place. When some type of strain or heavy stress is placed on the STF-soaked KEVLARŪ, the material goes from being flexible to completely rigid. Once rigid, the fabric does not move, so a bullet, arrow or knife cannot move past. In tests, projectiles actually bounced off the STF-treated KEVLARŪ!

Natural Armor Kevlar is by far the most common fiber used to make body armor, but other materials are being developed. In fact, one fiber being tested is spider silk. Yes, spider silk. Goats have been genetically engineered to produce the chemical constituents of spider silk. The resulting material is called Biosteel. A strand of Biosteel can be up to 20 times stronger than an equivalent strand of steel. Spider silk isn't the only natural material being tested for armor. Researchers are currently studying seashells, specifically the inner layer of mollusk shells commonly known as "mother of pearl." Mother of pearl or "nacre" is made up of two relatively weak materials. However, it is incredibly durable. This durability is due to its structure -- a series of millions of incredibly tiny plates or scales. Scientists are focusing their studies on nanometer-sized areas of these plates. They believe that eventually, the structural design could be duplicated using much stronger materials, which would then be used to create armor.