Interaction forces between carbon nanospheres: A molecular dynamics simulation study

In this work, the interaction forces between carbon nanospheres are studied using molecular dynamics (MD) simulations. It is shown that the conventional Hamaker approach cannot be directly applied to reliably estimate the van der Waals attraction and Born repulsion forces for nanospheres of different carbon materials. Yet, there are some common features identified, including a finite value of the forces at the surface separation d≈0 nm, a maximum ratio between the interaction forces obtained from the MD simulation and Hamaker approach at d≈0.4 nm, a turning point of interaction forces at d≈0.15 nm. These features can be quantitatively described with a similar mathematical form formulated for silica. Moreover, it is demonstrated that the mechanical contact force between carbon nanospheres at a low compression can be described by the classical Hertz model. Finally, the minimum gap between carbon nanoparticles in collision can be described by the conventional contact mechanics, which is adapted to evaluate the minimum gap.