When we think of bulletproof vests, our minds automatically jumps to Kevlar. It seems like Kevlar has to defend its title. New polyethylene nanofibers have been developed by scientists at MIT. These are both strong and tough and could be used as a body armor one day which would be less bulky than kevlar.
Prof. Gregory Rutledge is leading the team of researchers that created the nanofibers. They used an existing technique known as gel spinning, in which a polymer gel is extruded through a heated syringe and mechanically spun into strands. Their method differed slightly as they spun the gel through an electric field rather than by mechanical means.
The resulting nanofibers are only a few hundred nanometers in width. Materials don’t often show high strength and toughness at the same time, but due to some unknown reason, these fibers exhibit both these characteristics.
“Usually when you get high strength, you lose something in the toughness,” says Rutledge. “The material becomes more brittle and therefore doesn’t have the mechanism for absorbing energy, and it tends to break. It’s a big deal when you get a material that has very high strength and high toughness.”
When compared to carbon and ceramic fibers, it was discovered that the new nanofibers had the same strength but were much tougher than their counterparts. They are less dense and outperform traditional materials on a pound-for-pound basis. These should be relatively easy and inexpensive to manufacture and one day we might see them replacing kevlar.