Nano-pumping of fullerene and water molecules via a carbon nanotube in vacuum and aqueous environments

Abstract

Nano-pumping of molecules via a carbon nanotube (CNT) can be achieved by mechanical actuation and wave propagation through the tube wall which is generated by two oscillating tips. By using non-equilibrium molecular dynamics (NEMD) simulations, we investigate the effects of tip frequency and amplitude in the pumping of a C20 molecule through (13, 0) CNT in the vacuum environment. The pumping action (C20 ejection) does not succeed in all tip frequencies and amplitudes, and there are optimum points in which successful pumping takes place. In one of these successful pumping conditions (specific tip frequency and amplitude), we have performed NEMD simulations of water and fullerene pumping in an aqueous environment and found that mechanical wave propagation is much weaker in such an environment and the pumping of C20 molecule does not succeed. Our simulations show that mechanical wave velocity along CNT can reach as a high as 5000 m/s. And during the pumping process, the C20 molecule accelerates due to transferring kinetic energy and the velocity remains constant since no external force is applied on C20 molecule.