Columbia University study proves graphene “stronger than ever”

Posted on 3 Jun 2013

A new study published by Columbia Engineering researchers proves that “wonder material” graphene can maintain its strength even when it’s not at atomic scale.

James Hone and Jeffrey Kysar, professors of mechanical engineering, showed how the material, even when stitched together from several small grains, is almost as strong as the perfect lattice. Previous experiments had indicated it tends to weaken when used in large sheets.

Hone and Kysar said: “Defect-free, pristine graphene exists only in very small areas. Large-area sheets required for applications must contain many small grains connected at grain boundaries, and it was unclear how strong those grain boundaries were. In this paper, we report on the strength of large-area graphene films grown using chemical vapor deposition, and we’re excited to say that graphene is back and stronger than ever.”

While the methods commonly used to post-process CVD-grown graphene appear to weaken grain boundaries, a new process devised by the Columbia professors avoid all damages.

Gwan-Hyoung Lee, a postdoctoral fellow who works in Hone’s laboratory, commented: “We substituted a different etchant and were able to create test samples without harming the graphene. Our findings clearly correct the mistaken consensus that grain boundaries of graphene are weak. This is great news because graphene offers such a plethora of opportunities both for fundamental scientific research and industrial applications.”

Graphene is considered the strongest material ever created.

Hone and Kysar found that the chemical used to remove the copper substrate makes the graphene considerably weaker. Their experiments, however, led to the conclusion that CVD graphene is about 90% as strong as the ideal crystal.

Hone said: “This is an exciting result for the future of graphene, because it provides experimental evidence that the exceptional strength it possesses at the atomic scale can persist all the way up to samples inches or more in size.”

Graphene could have several applications, from flexible electronics (TV screens rolling up like posters) to strengthening components that could replace carbon fiber.

There is growing interest for the material in the UK: the University of Cambridge recently announced it is building a £25 million facility at the end of the year, to study possible industrial applications of graphene.