Electrokinetics of Particles and Fluids

Morgan, Hywel, Green, Nicolas and Sun, Tao (2008) Electrokinetics of Particles and Fluids. In, Ho, Chih-Ming (ed.) Microtechnology and Nanotechnology in Biomedical Applications. Oxford University Press. (Submitted)

Abstract

Microfluidic systems offer integration of multiple functions on a single platform. Automated or remote manipulation and analysis of particles and fluids is a key element in micro-technologies and Lab-on-a-Chip. In most Lab-on-a-Chip systems, samples are suspended in an aqueous electrolyte: a conducting fluid medium. The reduction in size of these systems leads to a number of changes in system behaviour, for example the behaviour of fluid is dominated by viscosity. Also it is reasonable easy to generate very large electric fields and field gradients in micro-systems using quite low voltages. External pumps are often used to move fluid, but there is a growing interest in using electrokinetics to move liquids and solid particles within micro-chips using integrated electrodes. Electrokinetics is particularly attractive on the scale of micro-fluidics systems. The forces are easy to control by designing optimum electrode structures and choice of field and frequency. In this chapter we review the theory of electrokinetics in DC and AC fields, and its application to the manipulation of particles, including dielectrophoresis. We then discuss the theories and application of electrohydrodynamic effects in microsystems, focusing on electroosmosis (in DC and AC fields) and electrothermal effects in AC field. We finish with a short discussion of scaling effects.

This record has no associated files available for download.

Contributors

Author: Hywel Morgan

Author: Nicolas Green

Download statistics