Carbon nanotube screening effects on the water-ion channels.

A self-consistent tight-binding method is used to investigate the screening effects of semiconducting and metallic single-wall carbon nanotubes (SWCNTs) when the water molecules and various charged ions pass through the nanotubes. The trajectories of ions and water molecules are obtained from molecular dynamics simulations. It is shown that metallic SWCNTs have much stronger screening abilities than semiconducting SWCNTs. Our results indicate that it is possible to distinctly identify different ions and also to differentiate between armchair and zig-zag nanotubes.