Field effect control of electrokinetic transport in micro/nanofluidics

Electrokinetics has emerged as one of the most promising techniques to transport and manipulate ions, fluid and particles in micro/nanofluidic devices. Field effect permits flexible and rapid control of the surface charge property on the channel wall, which in turn offers a more sophisticated control of the electrokinetic transport phenomena in micro/nanofluidics. In the field effect control, a potential named as gate potential is applied to a gate electrode patterned on the outer surface of the dielectric channel wall in contact with an aqueous solution, and the imposed radial electric field can effectively modulate the surface potential at the channel/liquid interface, resulting in the redistribution of ions and accordingly the ionic conductance of a nanochannel. The modulation of the surface potential at the channel/liquid interface can also affect the electrokinetic transport of fluids and particles. This tutorial review elucidates the physical mechanism and discusses some typical results of the field effect control of ion, fluid and particle electrokinetic transport in micro/nanofluidics. (c) 2011 Elsevier B.V. All rights reserved.