Modeling and Analysis of the Geometry-Dependent Mechanical and Thermal Properties of Coiled Carbon Nanotubes

Coiled carbon nanotubes (CNTs) have attracted much attention thanks to their unique geometrical structure along with outstanding mechanical and thermal properties. However, the relationship between the geometrical parameters and mechanical and thermal properties of coiled CNTs remains largely unexplored. Herein, coiled CNTs are constructed with various geometries by phase-field crystal (PFC) modeling and their mechanical and thermal properties are investigated by molecular dynamics (MD) simulations. It is found that the effect of geometrical parameters of coiled CNTs on the Young's modulus can be well captured by analytical formulas derived from the mechanical spring tube model. These extensive MD simulations show that the Young's modulus of coiled CNTs increases with an increase in coil pitch l and CNT radius r, but decreases with an increase in coil radius R. Furthermore, using the nonequilibrium MD (NEMD) method, it is found that the thermal conductivity of coiled CNTs decreases with an increase in coil radius R, but increases slightly with an increase of coil pitch l and CNT radius r. Valuable insights into the mechanical and thermal properties of coiled CNTs are provided and the findings here may serve as useful guidelines for the design of coiled CNTs for device applications.