Mechanical properties of graphene-CNT van der Waals heterostructures: a molecular dynamics study

We find stiffness properties of van der Waals heterostructures made of graphene and carbon nanotubes (CNTs) using molecular dynamics (MD) simulations. The variation of the stiffness tensor is studied at different temperatures for structures with changing CNT density, and orientations. Orthotropic structures with unidirectional CNTs have high stiffness ∼300-500 GPa, in one direction. Structures with transverse isotropy show stiffness of ∼150-350 GPa along two mutually perpendicular directions. The orthotropic structures also show greater stiffness with increasing CNT density, while the others are insensitive to it. In general,the stiffness constant values are decrease as temperatures increase. The results can aid in determining useful heterostructure configuration for a particular application and in finding overall stiffness of devices having additional components.