Atomistic Simulation of Mechanical Properties of ${\mathrm{Au}}_{32}$ Cluster Peapod Structures: Molecular Dynamics and Density Functional Theory

This study investigates the effect of encapsulating a golden fullerene (${\mathrm{Au}}_{32}$) cluster on the mechanical properties of a single-walled carbon nanotube (SWCNT) and a boron-nitride nanotube (BNNT). First, the geometrical parameters of the nanopeapods were optimized using the density functional theory (DFT) method. The DFT results demonstrated that the strength of interaction between the ${\mathrm{Au}}_{32}$ cage and a BNNT was stronger than that between the ${\mathrm{Au}}_{32}$ cage and SWCNT. The molecular dynamics (MD) method was then applied to calculate mechanical properties such as Young’s modulus, failure stress, and failure strain using a stress–strain plot. The mechanical results indicated that encapsulating the ${\mathrm{Au}}_{32}$ cluster reduced the Young’s modulus and failure stress of both a SWCNT and BNNT, whereas the failure strain did not observably change. To validate these results, a ${\mathrm{C}}_{60}$ cage was inserted inside an SWCNT in the most exothermic situation. The MD calculation indicated that, similar to the effect of ${\mathrm{Au}}_{32}$ in the ${\mathrm{Au}}_{32}$-nanotube peapod, ${\mathrm{C}}_{60}$ reduced the mechanical properties of the SWCNT.