The morphologies of Lennard-Jones liquid encapsulated by carbon nanotubes

Using molecular dynamics simulations, we studied the morphologies of Lennard-Jones liquid encapsulated in carbon nanotubes (CNTs) for a wide range of liquid–CNT interaction, system size and temperature. The morphology of liquid is found to be sensitive to the filling ratio of liquid (a ratio of liquid volume to the available volume of CNT pore) and the liquid–CNT interaction. The ‘phase diagram’, namely by the morphologies versus the liquid–CNT interaction and the filling ratio, is obtained. In most cases, the liquid inside CNTs forms a thin liquid shell attached to a carbon wall when the filling ratio is small. With the increasing of the filling ratio, liquid tends to form droplet. As the filling ratio increases further, liquids form a cylinder with finite length. Finally, the whole inner space of CNT was filled with liquid when the filling ratio is large enough. Current studies could shed light on the adsorption and flow of liquid inside CNTs.

► The morphologies of liquid encapsulated by carbon nanotubes were investigated.
► The phase diagram versus the liquid–tube interaction and the filling ratio was obtained.
► The morphologies were analyzed based on the balance between surface and interface energy.