We investigated the structure and mechanical properties of coiled carbon nanotubes (CNTs) using phase field crystal (PFC) and molecular dynamics (MD) simulations. While coiled CNTs are promising as nanosprings, conventional defect-based design methods may not ensure structural stability. We developed a PFC simulation method on helical tube surfaces using the Laplace-Beltrami operator and examined not only random fluctuations but also other initial conditions. The results showed that the final CNT structure and defect distribution strongly depend on these initial conditions. Tensile simulations revealed that inappropriate initial conditions cause defect concentration, reducing spring performance. Non-close coiled CNTs exhibited a clear linear relationship between potential energy and squared displacement, indicating sufficient elasticity. In contrast, close coiled CNTs showed limited elastic regions due to van der Waals interactions. Our study demonstrates that controlling PFC initial conditions is crucial for designing helical CNTs with optimal spring properties and proposes a theoretical framework for such design.
Matsuzaki et al. (Wed,) studied this question.