Nov 24, 2011
Mechanics of boron nitride nanosheets explained
A new model to describe the mechanical properties of hexagonal boron nitride nanosheets has been developed by researchers from the University of Bristol (ACCIS and Bristol NSQI Centre) and Swansea University (Multidisciplinary Nanotechnology Centre). The model illustrates an important difference in terms of deformation mechanisms between boron nitride (B-N) single sheets and graphene, justifying the experimental results on B-N nano-layered systems found by other researchers. The model allows users to perform compact and simplified simulations to design novel nanosensors and composites based on B-N nanoinclusions.
The team offers an alternative analytical molecular mechanics approach for hexagonal BN sheets based on a unified method, which determines an equivalent set of mechanical properties describing the BN bonds. This approach is an extension of the atomistic-continuum method developed for pristine, hydrogenated and bilayer graphene, and the thermomechanical properties of carbon nanotubes.
Using the method, the group shows that it is possible to describe in an analytical and compact form the in-plane mechanical properties of B-N sheets (Young's and shear modulus, as well as Poisson's ratio) using only one angular stiffness and stretching coefficient, both depending analytically from the force models used (DREIDING and UFF) and the equivalent mechanical behaviour of the BN bonds.
The scientists reveal that the proposed analytical approach not only compares well with existing ab initio and MM approaches in the open literature, but also provides an insight into the various deformation mechanisms that rule the in-plane elasticity of BN sheets and their differences from planar carbon-based nanostructures.
Additional information is available in the journal Nanotechnology.
About the author
Fabrizio Scarpa is professor of Smart Materials and Structures and a member of the Advanced Composites Centre for Innovation and Science (ACCIS) at the University of Bristol, UK.