title: Origin of giant ionic currents in carbon nanotube channels.
abstract: Fluid flow inside carbon nanotubes is remarkable: transport of water and gases is nearly frictionless, and the small channel size results in selective transport of ions. Very recently, devices have been fabricated in which one narrow single-walled carbon nanotube spans a barrier separating electrolyte reservoirs. Ion current through these devices is about 2 orders of magnitude larger than predicted from the bulk resistivity of the electrolyte. Electroosmosis can drive these large excess currents if the tube both is charged and transports anions or cations preferentially. By building a nanofluidic field-effect transistor with a gate electrode embedded in the fluid barrier, we show that the tube carries a negative charge and the excess current is carried by cations. The magnitude of the excess current and its control by a gate electrode are correctly predicted by the Poisson-Nernst-Planck-Stokes equations.
authors: Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
authors: Pei
authors: P
authors: Pang
authors: Jin
authors: J
authors: He
authors: Jae Hyun
authors: JH
authors: Park
authors: Predrag S
authors: PS
authors: Krstić
authors: Stuart
authors: S
authors: Lindsay
mesh_terms: D004563:Electrochemistry; D007473:Ion Channels / Q000378:metabolism*; D037742:Nanotubes, Carbon; D009995:Osmosis
chemical_list: D007473:Ion Channels; D037742:Nanotubes, Carbon