Rice, Tsinghua theorists find junctions in polycrystalline
graphene sap strength of super material
Graphene, the single-atom-thick form of carbon, has become
famous for its extraordinary strength. But less-than-perfect sheets of the
material show unexpected weakness, according to researchers at Rice University
in Houston and Tsinghua University in Beijing.
The kryptonite to this Superman of materials is in the form
of a seven-atom ring that inevitably occurs at the junctions of grain
boundaries in graphene, where the regular array of hexagonal units is
interrupted. At these points, under tension, polycrystalline graphene has about
half the strength of pristine samples of the material.