Collective transport of ions through carbon nanotubes under alternating electric field.

The transport behavior of potassium ions through carbon nanotubes (CNTs) under the effect of moving surface charges is studied by using non-equilibrium molecular dynamics and the Monte Carlo method. Two motion patterns of the surface charges, axial translation and radial vibration, are investigated. We found that when the surface charge is translated in the axial direction, there is an optimal translation velocity to maximize the particle flow density (PFD ), and the specific value of this optimal translation velocity is related to the surface charge period and the charge amount. When the surface charge vibrates in the radial direction, the PFD under the negative charge presents a step-type-decrease trend with an increase of the vibration frequency, and the trend is independent from the charge amount and the vibrating period. Our results provide new ideas for nanoscale transport devices and also provide possible insights into the transport mechanisms of biological ion channels. [ABSTRACT FROM AUTHOR]