| AVS 54th International Symposium | |
| Nanometer-scale Science and Technology | Monday Sessions |
| Session NS-MoM |
| Session: | Nanoscale Assembly and Manipulation I |
| Presenter: | A. Kutana, California Institute of Technology |
| Authors: | A. Kutana, California Institute of Technology K.P. Giapis, California Institute of Technology |
| Correspondent: | Click to Email |
We present molecular dynamics simulations of solidification and melting of mercury nanoparticles inside carbon nanotubes as a function of nanotube diameter. The mercury liquid is described by an ab initio potential for mercury dimer, rescaled to match the experimental density at 300K and melting point of mercury. The liquid-wall interactions are optimized based on the wetting angle of a mercury drop on graphite. The liquid-solid phase transition is marked by a discontinuity of the energy when monitored as a function of temperature. A significant depression of the melting point of mercury nanoparticles is predicted as the nanotube diameter decreases from 5.4 nm to 1.4 nm. The transition is less pronounced in smaller tubes, as the limit of one-dimensional system is approached. Below the freezing point, the crystal structure of solid nanoparticles is represented by a set of concentric shells in small nanotubes, while larger nanotubes show multiple domains with bulk crystal structure. Above the melting point, the central part of the nanoparticle is amorphous, while the liquid within a few atomic layers of the wall remains partially ordered. Near-wall liquid density profiles exhibit oscillation with the amplitude that increases as the tube diameter becomes smaller. In overall, the ordering inside nanotube cavities is stronger in comparison with the liquid near a flat wall. The contact angles are predicted to be larger inside nanotubes than on flat graphene sheets, indicating less favorable conditions for wetting on concave surfaces.