Scientists at MIT have developed a process that can produce ultrafine Nano fibres. Their diameter is so small that they have to be measured in nanometers. These fibres are exceptionally strong and durable. The fibres produced with this new method have a multitude of applications from medical to military and are inexpensive to manufacture.
The new method is being called gel electrospinning and has been produced by MIT professor of chemical engineering Gregory Rutledge and postdoc researcher Jay Park.
When it comes to material science there is usually a lot of tradeoffs during development. “Strength and toughness are a pair like that, usually when you get high strength, you lose something in the toughness. The material becomes more brittle and therefore doesn’t have the mechanism for absorbing energy and it tends to break” Rutledge explains.
This newly developed method is almost an exception to the rule, with most of the tradeoffs being eliminated. “It’s a big deal when you get a material that has high strength and high toughness,” Rutledge said.
Electricity is Key
The new method varies from traditional ‘Gel Spinning’ methods by adding an electrical force to the process. The outcomes are ultrafine nanofibres of polyethene that meet or exceed some of the toughest fibres know, such as Kevlar and Dyneema.
“We started off with a mission to make fibres in a different size range, namely below 1 micron because those have a variety of interesting features in their own right and we’ve looked at such ultrafine fibres, sometimes called nanofibers, for many years. But there was nothing in what would be called the high-performance fibre range.”
Rutledge says “What really sets these apart is what we call specific modulus and specific strength, which means that on a per-weight basis they outperform just about everything.” Modulus refers to how much a fibre can resist being stretched
When the new fibres are compared to ceramic and carbon fibres that are common in current composite materials, the new gel-electrospun polyethene fibres have similar strength characteristics but are much tougher with a lower density. “That means that pound for pound, they outperform the standard materials by a wide margin”, Rutledge says
The new fibres might lead to better protective materials that are just as strong as existing ones but less bulky, giving rise to better and more practical bulletproof vest. Rutledge adds, “they may have applications we haven’t thought about yet because we’ve just now learned that they have this level of toughness.”
Source: MIT University