USouthampton Optimizes the Strength of Glass Nanofibers

The discovery that silica nanofibers are more resilient when their size is decreased has resulted in creation of the strongest, lightest-weight silica nanowires ever created. The findings could transform the aviation, marine and security industries.

“Weight for weight, silica nanowires are 15 times stronger than high-strength steel and 10 times stronger than conventional GRP (glass reinforced plastic), said University of Southampton professor Sir David Payne, who recently received a knighthood from the Queen for his service to photonics. (See: Queen Knights Fiber Laser Pioneer) “We can decrease the amount of material used, thereby reducing the weight of the object. … Furthermore, we can produce silica nanofibers by the ton, just as we currently do for the optical fibers that power the Internet.”

The nanowires are composed of two of the most common elements in the Earth’s crust — silica and oxygen — making it inexpensive and sustainable to exploit, said Payne, director of the university’s Optoelectronics Research Centre (ORC). Historically, carbon nanotubes were the strongest material available, but high strengths could be measured only in very short samples and just a few microns long, providing little practical value.

Now, the research conducted by Payne and ORC Principal Research Fellow Dr. Gilberto Brambilla has resulted in the creation of fibers that can be manufactured in lengths potentially thousands of kilometers long.

Scientists at the University of Southampton have developed the strongest, lightest glass nanofibers in the world after discovering that the material becomes more resilient the smaller it gets. Dr. Gilberto Brambilla mounts a fiber on the nanowire fabrication rig. Courtesy of the University of Southampton.

“Usually, if you increase the strength of a fiber, you have to increase its diameter and, thus, its weight,” Brambilla said. “But our research has shown that as you decrease the size of silica nanofibers, their strength increases, yet they still remain very lightweight. We are the only people who currently have optimized the strength of these fibers.”

The five-year-long investigation, supported by £500,000 (about $806,200) Fellowship funding from the Royal Society, was no easy feat, Brambilla told researchers recently at a special seminar at the Kavli Royal Society International Center.

“It was particularly challenging dealing with fibers that were so small,” he said. “They are nearly 1000 times smaller than a human hair, and I was handling them with my bare hands. It took me some time to get used to it, but … I was able to discover that silica nanofibers become stronger the smaller they get. In fact, when they become very, very small, they behave in a completely different way. They stop being fragile and don’t break like glass but, instead, become ductile and break like plastic. This means they can be strained a lot.”

“Our discovery could change the future of composites and high-strength materials across the world and have a huge impact on the marine, aviation and security industries,” Brambilla said. “We want to investigate their potential use in composites, and we envisage that this material could be used extensively in the manufacture of products such as aircraft, speedboats and helicopters.

The findings have already generated extensive interest from companies worldwide. Tests are currently being carried out globally into the potential future applications for nanowires.

For more information, visit: www.southampton.ac.uk