(8j) Three-Dimensional Numerical Modeling of Electrothermal Flows in Insulator-Based Dielectrophoresis Microdevices

Insulator-based dielectrophoresis (iDEP) has been established as a powerful tool for manipulating particles in microfluidic devices. In some of the most commonly encountered iDEP devices, such as the rectangular constriction microchannels, Joule Heating occurs due to the local amplification of the electric field within the constriction region. It results in an electrothermal force which manifests itself in the flow field in the form of circulations. Although the effects of Joule heating on electroosmotic flow and electrophoretic separation have been studied extensively in capillary and microchip electrophoresis, very little work has been done in analyzing Joule heating and electrothermal flow in iDEP microdevices. The previous work in this direction has focused on a two-dimensional model of the microchannel, and has not accounted for a transient behavior of the flow and temperature fields. This work demonstrates the first full-scale transient three dimensional numerical simulation of the Joule heating induced electrothermal flow in an iDEP device with a rectangular constriction microchannel in the PDMS layer. The effects on electrothermal flow will be studied for various parameters including electric field, channel dimension, solution conductivity, and PDMS thickness.