Title: Transport of Fluid, Current and Analytes in Nanofluidic Channels

Speaker: Dimiter N. Petsev, Department of Chemical and Nuclear Engineering, University of New Mexico

Location: Building 980, Room 95 (Sandia NM), Building 915, Room S101 (Sandia CA)

Brief Abstract: The flow of fluids (pure liquids and solutions) in very narrow channels enjoys a substantial attention with the rapid development of the fields of micro and nanofluidics. Miniaturized integrated fluidic devices have a great potential for enhanced separation and analysis by reducing the required time and the sizes of the samples. In channels of submicron dimension the electrokinetic phenomena play a particularly important role since the electric double layers formed at the walls can occupy a substantial part of the channel volume. In our work we present a concise theory that allows obtaining analytical expressions for the transport of fluid (electroosmotic flow), ions (electric current) and dissolved charged molecules (analytes) in the case of a weak double layer overlap. The approach is applicable not only to symmetric but also to asymmetric 2:1 and 1:2 electrolytes solutions in slit shaped nanoscale channels and cylindrical nanocapillaries. In the case of very thick double layers (compared to the channels width) the transport problems are treated numerically.  Applying transverse voltage bias across the channel wall can be used in an attempt to control the transport and such devices are often called “fluidic field effect transistors”. Our model quantifies the effect of the voltage bias on the zeta potential of the channel wall and therefore can be used for prediction of transport and optimization of separations in such fluidic devices.

CSRI POC: Michael Parks, (505) 845-0512