In recent years, researchers have been making great strides in making new materials from really tiny parts — and by tiny, we're talking things measured in nanometers, a unit so small that it's probably difficult for most of us to even imagine it.
If you want to try visualizing nanoscale, consider that a strand of DNA in one of your cells is about 2.5 nanometers in diameter, and a sheet of paper has a thickness of 100,000 nanometers. What's the value of such miniscule structures? For one, it's possible to make nanomaterials that are incredibly strong, but also lightweight, and to equip them with other properties, such as the ability to conduct electricity.
Okay, so maybe that doesn't sound quite mind-blowing enough. Try this, then: It now looks as if it might be possible to make threads of really, really small diamonds that are strong enough to support a giant elevator stretching for miles all the way up into space.
That prospect has been raised by Penn State University researchers' recent discovery of how to produce ultra-thin diamond nanothreads, which might turn out to be the strongest manmade materials ever created.
The team created a long, thin strand of carbon atoms, arranged in the same fashion as the fundamental unit of a diamond's structure — zig-zag "cyclohexane" rings of six carbon atoms bound together, in which each carbon is surrounded by others in the shape of a tetrahedron. If that's too complex-sounding, envision the nanothread as a necklace strung together from the smallest possible diamonds — made of stuff that's extraordinarily stiff and strong.
"It's potentially among the strongest materials, if not the strongest, ever known," says Penn State chemistry professor John Badding, one of the study's authors.
If researchers could create a perfect diamond nanothread with no defects, Badding says, it could match or exceed the qualities of sp2 carbon nanotubes, formed by rolling a nanofiber sheet into a tube, which up to this point have been the strongest manmade materials created.
Of course, if you've trying to show people just how super-strong something is, it helps to have an example of something you could do with it. (You know, just like the old Crazy Glue commercial that shows the guy in the hardhat, who glues himself to a steel girder and then dangles from it.)
Up Past the Atmosphere
When pressed, Badding thought of the idea of using diamond nanothreads to build a space elevator — a concept in which a cable attached to the Earth at one end and a stationary satellite at the other would allow humans, equipment and other cargo to ascend into space. It's an idea that was first envisioned by the Russian space scientist Konstantin E. Tsiolkovsky way back in 1895, and popularized by science fiction author Arthur C. Clarke in his 1979 novel "The Fountains of Paradise."
A space elevator might make travel to and from space vastly cheaper, safer and less stressful than it is today. But building one would cost as much as $100 billion, by one estimate. And you'd need to make it from stuff strong enough to withstand the tremendous forces to which such a structure would be subjected.
While Badding stresses that the development of diamond nanothreads is at the very early stages, a Canadian company recently granted a U.S. patent for a 12.4 mile-high space elevator design seems pretty interested in looking at the new material. (See video below.)
"If in commercial production the thread's strength is significantly higher than that of Kevlar, then we may be able to go even higher," says Thoth Technology chief technology officer Brendan Quine via email.
Quine said that diamond nanothreads could be used to reinforce the pneumatic elements of the proposed space elevator's structure. "We are going to need them in large quantities though," he added. "Our structure has a mass similar to that of the world's largest supertankers used to move oil around the world."