Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) Simulations of the Effects of Chirality and Diameter on the Pullout Force in a Carbon Nanotube Bundle

The unique mechanical, electrical, and thermal properties of carbon nanotube (CNT) molecules place them at the forefront of nanotechnology. The mechanical properties of carbon nanotubes such as high tensile strength and modulus provide an effective pathway for better construction materials. Before this potential can be realized, effective techniques of creating load transfer in bulk material must be developed. Carbon nanotubes possess a variety of chiralities and diameters and can cluster into self-organizing, aligned bundles caused by van der Waals (vdW) forces. This paper describes the results of molecular mechanics simulations using the large-scale atomic/molecular massively parallel simulator (LAMMPS) molecular dynamics code to examine the effect that chirality and diameter have on the pullout force of a single tube from a bundle with hexagonal closest packing (HCP). Pullout force is defined as the force required to extract a tube from a bundle. The different chiralities and diameters create different corrugated surfaces and different areas of contact that influence pullout force. Studying the interaction between CNTs is essential for improving the fundamental understanding of load transfer from CNT to CNT. Additionally, since larger diameter CNTs deform against one another in a bundle, the relationship between diameter and pullout force is quantified in this paper. This research will be used as a basis for studying more advanced load transfer techniques such as twisting, sidewall functionalization, and knotting.