Rice University researchers have determined from first-principle calculations that carbyne would be the strongest material yet discovered. The carbon-atom chains would be difficult to make but would be twice as strong as two-dimensional graphene sheets. (Image Credit: Vasilii Artyukhov/Rice University)
Carbyne will be the strongest of a new class of microscopic materials if and when anyone can make it in bulk.
If they do, they’ll find carbyne nanorods or nanoropes have a host of remarkable and useful properties, as described in a new paper by Rice University theoretical physicist Boris Yakobson and his group. The paper appears this week in the American Chemical Society journal ACS Nano.
Carbyne is a chain of carbon atoms held together by either double or alternating single and triple atomic bonds. That makes it a true one-dimensional material, unlike atom-thin sheets of graphene that have a top and a bottom or hollow nanotubes that have an inside and outside.
According to the portrait drawn from calculations by Yakobson and his group:
- Carbyne’s tensile strength – the ability to withstand stretching – surpasses “that of any other known material” and is double that of graphene. (Scientists had already calculated it would take an elephant on a pencil to break through a sheet of graphene.)
- It has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.
- Stretching carbyne as little as 10 percent alters its electronic band gap significantly.
- If outfitted with molecular handles at the ends, it can also be twisted to alter its band gap. With a 90-degree end-to-end rotation, it becomes a magnetic semiconductor.
- Carbyne chains can take on side molecules that may make the chains suitable for energy storage.
- The material is stable at room temperature, largely resisting crosslinks with nearby chains.
That’s a remarkable set of qualities for a simple string of carbon atoms, Yakobson said.
Researchers at Rice University have used a computer simulation to calculate that carbyne, a monodimensional chain of carbon atoms, is twice as strong as carbon nanotubes and three times stiffer than diamond. If their findings are correct and the challenges posed by manufacturing it can be overcome, then carbyne could prove an incredibly useful material for a wide range of applications.
In 2016, it was successfully grown:
After eluding scientists for more than 50 years, a team of researchers has now found a way to not only synthesize carbyne, but to mass produce it.
This one-dimensional form of carbon is thought to be stronger than any other known to scientists, surpassing the stiffness of diamond by more than 40-fold.
In the new method, the researchers have used a double-walled carbon nanotube to grow stable carbon chains of record-breaking lengths.
- Carbyne is an infinitely long and truly one-dimensional form of carbon
- It is thought to be 40x stiffer than diamond and twice as stiff as graphene
- The material has remained elusive for years as it is extremely unstable
- Now, researchers have grown ultra-long carbon chain of 6,400 atoms
Carbyne was first proposed in 1885 by Adolf von Baeyer, who described the existence of linear acetylenic carbon – or an infinitely long carbon chain – known as carbyne.
But, the researcher warned it would remain elusive due to its extreme instability.
Led by Thomas Pichler, researchers from the University of Vienna have now developed a way to bulk produce carbon chains made up of more than 6,400 carbon atoms.
Previously, the record length for a carbon change was roughly 100 carbon atoms.
To achieve the new length, the researchers created double-walled nanotubes by rolling two layers of graphene.
The ultra-long carbon chains were then grown inside of these tubes, which create a stable environment.
This method allowed the team to form carbon chains more than 50 times longer than the previous record holder.
Researchers from the University of Vienna in Austria report in Nature Materials that they’ve managed to synthesize the material far more successfully than ever before. It’s proved so tricky in the past because Carbyne is a long one-dimensional chain of carbon atoms linked one to the other. Its structure makes it highly reactive, which means that as quickly as it’s manufactured, it’s destroyed.
But the Austrian researchers have found a way to make it while avoiding such destruction. They took two sheets of graphene, laid them on top of each other, then rolled the whole thing up to create a double-walled tube. Think of it as a graphene Thermos. Then, they synthesized the Carbyne inside the tube, providing a protective casing which allowed the material to remain in tact.
The record for stringing together carbon atoms like this in the past had been 100 in a row; now, the team can put 6,400 atoms together, and have them remain in a chain for as long as they want. That is, of course, as long as they sit inside the carbon Thermos. It remains to be seen how useful Carbyne will be whilst wrapped up, but for now it’s the best that researchers can achieve.
According to theoretical models, carbyne has mechanical properties that are unmatched by any known material, as it even outperforms the mechanical resistance and flexibility properties of graphene and diamond. Furthermore, its electronic properties are pointing towards new nano-electronic applications, such as in the development of new magnetic semiconductors, high power density batteries, or in quantum spin transport electronics (spintronics). However, the researchers point out that to do this it would be necessary to extract these ultra-long, linear carbon chains from the double-walled nanotube containing them and stabilise them in some liquid environment.