Surface-charge-governed ion transport in nanofluidic channels.
A study of ion transport in aqueous-filled silica channels as thin as 70 nm reveals a remarkable degree of conduction at low salt concentrations that departs strongly from bulk behavior: In the dilute limit, the electrical conductances of channels saturate at a value that is independent of both the salt concentration and the channel height. Our data are well described by an electrokinetic model parametrized only by the surface-charge density. Using chemical surface modifications, we further demonstrate that at low salt concentrations, ion transport in nanochannels is governed by the surface charge.
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Derek
D
Stein
Maarten
M
Kruithof
Cees
C
Dekker