Collaborating teams apply findings developed at macroscale to materials at atomistic scale

Summer 2010

PROBLEM

Graphene, discovered in 2004, is the thinnest known material. Because of its unique geometry — a single-atom thickness — fundamental questions about its mechanical performance remain unknown. A research team carried out a combined computational, theoretical and experimental study to see if an understanding of materials at the macroscale could be applied across the continuum to graphene.

MIT Professor Pedro Reis and co-authors wrote a series of papers explaining that the triangular-shaped tears that occur when a thin film is detached from a substrate are a signature mechanical behavior arising from the interaction of the three types of energy in the system: elasticity, adhesive energy and fracture energy. As the tape is pulled, the bending energy in the fold is converted into the surface energy of fracture and adhesion. Graphene inventor Kostya Novoselov, a fellow at the University of Manchester, had observed similar shaped tears at the nanoscale; when two-dimensional layers of graphene are scraped off graphite, they have a characteristic triangular shape. The researchers wondered if the ana