Carbon Nanotubes as Nanofluidic Devices

S. Lindsay
Arizona State University, US

Keywords: carbon nanotubes, CNT

Summary:

Using SEM to align lithography with CVD-grown single walled carbon nanotubes (SWCNTs), it is possible to construct devices in which a single SWCNT connects two fluid reservoirs. “Electrophoretic” ion currents through these devices have an unusual dependence on ion concentration, a consequence of the dominance of eletroosmotic flow in these tiny channels. Surprisingly, translocation of molecules (including DNA) through SWCNTs can be signaled by very large increases in ion current through the tube, in sharp contrast to the usual current blockade caused by a molecule transiting a nanopore. Simulations by Predgrag Kristic and Jae Park at Oak Ridge National Labs show that this can be explained by enhanced ionic selectivity in the channel, since the electroosmotic current is the product of the fluid flow velocity and the ion imbalance in the channel.