Mechanical properties of zigzag-shaped carbon nanotubes: the roles of the geometric parameters

Abstract

In our previous work, we predicted that zigzag-shaped carbon nanotubes (Z-CNTs) show significant electromechanical properties where under uniaxial tensile strain, a semiconductor-to-metal or metal-to-semiconductor transition can be observed [Phys. Chem. Chem. Phys., 2013, 15, 17134–17141]. Thus, investigating the mechanical properties of Z-CNTs is of key importance for exploring their applications in mechanical and electromechanical devices. Here, a series of Z-CNTs of different geometric parameters were constructed and optimized using the density functional method. Mechanical properties, such as intrinsic strength, Young's modulus and elastic constant, were studied to find their relationships to geometric parameters. Generally, all of the intrinsic strength, Young's modulus and elastic constant increase with increasing tubular radius, but decrease with increasing the pitch. In particular, fitting formulae were given to describe the relationships between the intrinsic strength/Young's modulus and the tubular radius, which show exponential relationships. Explanations were also given for dependence of mechanical properties on the geometric parameters of the Z-CNTs.