Chirality dependence of carbon single-walled nanotube material properties: axial coefficient of thermal expansion.

Carbon nanotubes are one of the best candidates for applications where structural, thermal, and chemical stabilities are of great importance. Despite the fact that significant efforts have been devoted to study properties and behavior of the carbon nanotubes in recent years, there have not been sufficient results available on their thermoelastic properties. This paper investigates the chirality dependence of coefficient of thermal expansion of carbon single-walled nanotubes both analytically and numerically. The analytical approach in characterizing the chirality dependence of the coefficient of thermal expansion uses an asymptotic homogenization method. A second analytical interpretation follows a free-expansion strain method based on basic principles of thermoelasticity. The derived formulae make it easy to understand the dependencies of the nanotube thermoelastic properties on its geometrical parameters. The results from these analytical studies were verified using a finite element method. All three independent studies consistently demonstrate that the coefficient of thermal expansion of carbon single-walled nanotubes is independent of their chirality.