Two-Layered Graphene Becomes Harder than Diamond Upon Impact

It sounds like an innovation made for Superman himself. Researchers have recently developed an ultralight material that can become hard as diamond when struck by a bullet or other high-speed projectile. 

A team of physicists from the City University of New York detailed this new creation in their research published in the most recent edition of the journal Nature Nanotechnology. The team created diamine using layered sheets of graphene that harden and become nearly impenetrable when hit. 

"This is the thinnest film with the stiffness and hardness of diamond ever created," lead researcher Elisa Riedo, of the Advanced Science Research Center at the Graduate Center, CUNY, said in a statement.

[see-also]

Graphene is formed from elemental carbon when just a single sheet of carbon atoms aligned in a signature honeycomb structure. Simply stated, the CUNY team combined two layers of flexible graphene that are just one atom thick each. When those layers are molded and temporarily deformed by an exterior force or pressure (like a bullet), the layers snap together and form an entirely new structure with definitive and powerful new physical properties. It's also important to note that this 'superstrength' only occurs with two layers of graphene -- and no more. 

"Previously, when we tested graphite or a single atomic layer of graphene, we would apply pressure and feel a very soft film,” Riedo said in a statement issued with the new research. “But when the graphite film was exactly two-layers thick, all of a sudden, we realized that the material under pressure was becoming extremely hard and as stiff, or stiffer, than bulk diamond."

According to Riedo, the team is still developing practical applications of the material. Further research, she said, is needed to determine just how stable this process could be. The team also wants to see the transition from graphite to diamond in other conditions. 

When asked how long she believes this entire testing process would take, Riedo replied, "It's difficult to say, honestly. We will need investors."

Other Graphene-based Innovations

Graphene's properties seem to be endless, and those possibilities have kept researchers returning to the material time and again for further study. In fact, the CUNY team aren't the first ones to transform graphene into a 'supersuit' of sorts. 

In 2014, Rice University researchers tested the material's properties with microbullets and discovered that graphene's strength is determined by how well it stretches before tearing. Initially, Edwin Thomas and his team with Rice Lab intended to study another element of graphene entirely, but after beginning their experiments, they discovered another element to the material's superstrength. 

"We started writing the paper about the petals, but as we went along, it became evident that wasn’t really the story,” said Thomas, the William and Stephanie Sick Dean of Rice’s George R. Brown School of Engineering. “The bullet’s kinetic energy interacts with the graphene, pushes forward, stretches the film and is slowed down."

And, at the time of the study, "nobody had taken comprehensive measurements to its ability to absorb an impact," Thomas noted in the press release. Between the Rice and CUNY studies, it's clear that graphene keeps surprising researchers. It's just a matter of time before these supermaterial-based innovations become scaled up for public use.