Materials Innovation: Strong and Lightweight Silica Nanofibers
Researchers have developed silica nanofibers that are 15 times stronger than steel.
Globally, the quest has been on to find ultra-high-strength composites, leading scientists at the University of Southampton’s Optoelectronics Research Centre
(ORC) to investigate light, ultra-high-strength nanowires that are not compromised by defects. Historically, carbon nanotubes were the strongest material available, but high strengths could only be measured in very short samples just a few microns long, providing little practical value.
Now research by ORC Principal Research Fellow Gilberto Brambilla, Ph.D., and ORC Director Professor Sir David Payne has resulted in the creation of the strongest, lightest weight silica nanofibers—“nanowires” that are 15 times stronger than steel and can be manufactured in lengths potentially of thousands of kilometers.
Their findings are reportedly generating extensive interest from many companies around the world and could be set to transform the aviation, marine, and safety industries. Tests are currently being carried out globally into the potential future applications for the nanowires.
“With synthetic fibers, it is important to have high strength, achieved by production of fiber with extremely low defect rates, and low weight,” Brambilla says. “Usually if you increase the force that a fiber can stand, you have to increase its diameter and thus its weight, but our research has shown that as you decrease the size of silica nanowires their strength increases, yet they still remain very lightweight, thus they can stand stronger forces with lighter weight than other materials. We are the only people who currently have optimized the strength of these fibers.
“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. We want to investigate their potential use in composites and we envision that this material could be used extensively in the manufacture of products such as aircraft, speedboats, and helicopters.”
Professor Payne explains: “Weight for weight, silica nanowires are 15 times stronger than high-strength steel and 10 times stronger than conventional glass-reinforced plastic (GRP). We can decrease the amount of material used, thereby reducing the weight of the object.
“Silica and oxygen, required to produce nanowires, are the two most common elements on the Earth’s crust, making it sustainable and cheap to exploit. Furthermore, we can produce silica nanofibers by the ton, just as we currently do for the optical fibers that power the Internet.”
The research findings came about following five years of investigations by Brambilla and Payne using Gilberto’s £500,000 (~ $ 785,900) fellowship funding from the Royal Society. Brambilla shared his findings with fellow researchers at a special seminar he recently organized at the Kavli Royal Society International Centre in Buckinghamshire, UK.
“It was particularly challenging dealing with fibers that were so small,” he said. “They are nearly 1,000 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 using the state-of-the-art facilities at the ORC, 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. Up until now, most of our research has been into the science of nanowires, but in the future we are particularly interested in investigating the technology and applications of these fibers.”
For more information, visit www.orc.soton.ac.uk/omfds.html.
Editor’s note: This article originally appeared in ScienceDaily, www.sciencedaily.com.