Anisotropic nanomechanics of boron nitride nanotubes: Nanostructured "skin" effect

The stiffness and plasticity of boron nitride nanotubes an investigated using generalized tight-binding molecular dynamics and ab initio total energy methods. Due to boron nitride (BN) bond rotation effect, compressed zigzag BN nanotubes are found to undergo anisotropic strain release followed by anisotropic plastic buckling. The strain is preferentially released toward N atoms in the rotated BN bonds. The tubes buckle anisotropically toward only one end when uniaxially compressed from both. A "skin-effect" model of smart nanocomposite materials is proposed, which localizes the structural damage toward the skin or surface side of the material.