Abstract

AC electrokinetics is one of the widely used methods as an actuating mechanism in the lab-on-a-chip devices because of the absence of moving mechanical parts. In this paper, an analysis is done by using two perpendicular electrodes which are placed in V-shape to each other while maintaining an angle of 45 degrees with the third horizontal electrode. A semiconductive fluid was used to observe the microfluidic behavior and characteristics under the application of a DC biased AC signal. Applying the AC signal produced two different mechanisms of electrokinetics such as DC-biased AC electrothermal (ACET) and DC-biased AC electroosmosis (ACEO). In the ACEO process, a time-varying voltage was applied to the electrodes to create the double layer capacitance and zeta potential. This ACEO mechanism required lower voltage. On the other hand, the AC Electrothermal (ACET) flow produced a non-uniform electric field that generated spatially varying heat sources which in turn created a non-uniform temperature distribution. Two surface characteristics were also analyzed experimentally; one of these was by using the hydrophobic surface and the other used glass-surface only. At the microscale, mechanical microdevice encounter very high flow resistance and put stringent requirements on the strength of fluid channels, chambers and the interconnects. While many types of microfluidic manipulations can be effectively done by AC electrokinetics techniques, current research work focused on the observation of varying frequencies and voltages and their effects on microfluidic manipulations.

This content is only available via PDF.
You do not currently have access to this content.