• Dr. Gilberto Brambilla peering at a silicon nanofiber.

    Credit: Courtesy of the University of Southampton

    Dr. Gilberto Brambilla peering at a silicon nanofiber.

In the search for stronger, lighter materials, scientists have paid a lot of attention to particular allotropes of carbon—such as graphene and carbon nanotubes. The challenge presented by such materials, though, is that they can only be measured at very small sizes in laboratory conditions, making them difficult to work with.

Recently, scientists at the University of Southampton in the UK claimed to have developed an ultrastrong material that is more versatile, made of silica nanofibers. In fact, these are apparently the strongest silica nanofibers known—over 15 times stronger than high strength steel and 10 times stronger than glass reinforced plastic (GRP). Moreover, they can be produced at industrial-scale lengths of up to 1000s of kilometers, according to the scientists.

"Usually if you increase the strength of a fiber you have to increase its diameter and thus its weight, but our research has shown that as you decrease the size of silica nanofibers their strength increases, yet they still remain very lightweight," said Gilberto Brambilla with Southampton's Optoelectronics Research Center. "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 envisage that this material could be used extensively in the manufacture of products such as aircraft, speedboats and helicopters."

Nearly 1,000 times thinner than human hair, the silica nanowires behave in unexpected ways at the micro-scale. "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," Brambilla said. "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."

The finding suggests the possibility to create a new breed of high-performance composites that take advantage of the nanofibers' significant resilience. Moreover, since the material is made of two of the most common elements on the planet (silicon and oxygen), its development does not raise concerns about resource depletion.

Blaine Brownell is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.