The toughest materials are the most fibrous. Such materials are used from bulletproof vests to tires. Research has shown that the smaller the fibers are then the stronger and more resilient they become. Creating smaller fibers is challenging, especially at the nano-scale.
In a breakthrough, materials scientists based at Harvard John A. Paulson School of Engineering and Applied Sciences together with researchers from the Wyss Institute for Biologically Inspired Engineering at Harvard have developed a new process to make and collect nanofibers. These are very tiny strands created from dissolved polymers.
For the process, a liquid polymer solution is poured into a reservoir. Physical (centrifugal) forces then push the solution out through small holes. As the solvent evaporates and the polymers solidify and elongate to produce tiny, ultra-thin fibers. Through the spinning action the nano-fibers move in the stream of the vortex and become wrapped around a rotating collector at the base of the device. In tests ballistic resistant para-aramid nanofibers (the basis of Kevlar) have been successfully formed.
The new process allows scientists to and control the size and morphology of nano-fibers. The outcome is the creation of stronger and more durable materials that could be used to create bulletproof vests. The process is superior to conventional fiber development, such as via ‘Rotary Jet-Spinning’ or electrospinning. The new process has been described as ‘immersion Rotary Jet-Spinning.’
Speaking with Controlled Environments, lead researcher Professor Kit Parker said: “This advance is important because it allows us to manufacture ballistic protection that is much lighter, more flexible and more functional than what is available today.”
The findings are published in the journal Macromolecular Materials and Engineering. The research paper is titled “Production of Synthetic, Para-Aramid and Biopolymer Nanofibers by Immersion Rotary Jet-Spinning.”
