Graphene is strong, but new research could prompt engineers to look a little deeper as they consider the miracle material for applications.
The atom-thin sheet of carbon is touted not just for its electrical properties but also for its physical strength and flexibility. The bonds between carbon atoms are the strongest in nature, so a perfect sheet of graphene should withstand just about anything, which is why reinforcing composite materials is among the material’s potential applications.
Researchers Jun Lou at Rice University and Ting Zhu at Georgia Tech have measured the fracture toughness of imperfect graphene for the first time and found it to be somewhat brittle, however. While it’s still very useful, graphene is really only as strong as its weakest link, which they determined to be substantially lower than the intrinsic strength of graphene.
The researchers reported in the journal Nature Communications the results of tests in which they physically pulled graphene apart to see how much force it would take.
“Graphene has exceptional physical properties, but to use it in real applications, we have to understand the useful strength of large-area graphene, which is controlled by the fracture toughness,” said Zhu, an associate professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering.
Imperfections in graphene drastically lessen its strength. That’s important for engineers to understand as they think about using graphene for applications in which stresses on microscopic flaws could lead to failure.