Carbon is the element that just keeps on giving. Life wouldn’t be possible without it, of course. The ultra-hard mineral diamond is composed entirely of carbon. And materials scientists are pushing it to do increasingly clever things, skimming off single-atom-thick sheets to form graphene and then rolling them up to form graphene nanotubes, which could underpin powerful and efficient computer chips.
Now, carbon is been pressed into thin filaments just a few atoms wide, called diamond nanothread. Last year, the slim material was created in a lab from readily available benzene rings. Just this month, it was modified in computer simulations to show just how flexible it could be.
The computer simulations, led by Haifei Zhan at Queensland University of Technology, are perhaps as newsworthy as the results. As computing power has increased in recent years, experts have been predicting the rise of computational materials science, or the ability to test out new materialsin silico before we ever make them in the lab. It has the potential to drastically reduce the amount of time it takes to craft new materials by confining much of the trial and error process inside easily tunable computer simulations.
In this instance, Zhan and his team modeled what would happen if they altered the way benzene rings bonded to each other. (Specifically, they were investigating Stone-Wales defects.) Benzene rings form the building blocks of diamond nanothread in a process pioneered by John Badding and his team at Penn State University. By compressing liquid benzene under high pressure and then releasing it slowly, the carbon atoms rearranged in a way that linked them into a long, thread-like polymer.
Those polymers, though, could be brittle. Here’s Technology Review:
In particular, Zhan and co look at the two most common configurations. The first is straightforward polymerized benzene—a stack of these rings bonded together. This is a rigid molecule that becomes increasingly brittle as it gets longer. Constructing anything complex with long sections of poly-benzene would be like trying to sew with like uncooked spaghetti.
But there is another configuration of carbon atoms known as Stone-Wales defects, and these are much more malleable. Indeed, the Stone-Wales defects act like hinges connecting sections of poly-benzene.
In essence, diamond nanothread with Stone-Wales defects would be like the world’s smallest chain—sections of it would be rigid, but hinges between them would allow enough flexibility for the material to be formed into a variety of shapes and structures.
Zhan’s research was all done inside the bounds of a computer, so there’s still the issue of actually making the stuff. But his work shows the promise of diamond nanothread and, perhaps more importantly, computational materials science.