ELECTROHYDRODYNAMIC MODELING FOR MICROFLUIDIC DEVICES

Since the inception of microfluidics, the electric force has been exploited as one of the leading mechanisms for driving and controlling the movement of the operating fluid (electrohydrodynamics) and the charged suspensions (electrokinetics). Electric force has an intrinsic advantage in miniaturized devices. Because the electrodes are placed cross a small distance, from. sub-millimeter to a few microns, a very high electric field is rather easy to obtain. The electric force can be highly localized with its strength rapidly decaying away from the peak. This makes the electric force an ideal candidate for spatial precision control. The geometry and placement of the electrodes can be used to design electric fields of varying distributions, which can be readily realized by MEMS fabrication methods. In this paper we examine several electrically driven liquid handling operations. We discuss the theoretical treatment and related numerical methods. Modeling and simulations are used to unveil the associated electrohydrodynamic phenomena. The modeling based investigation is interwoven with examples of microfluidic devices to illustrate the applications. This paper focuses on detailed physical simulations of component-level operations. Since the components must be integrated to form a functional system in order to provide desired services, system-level complexities in both architecture and execution also need to be addressed. Compared to the state of the art of computer-aided design for microelectronics, the modeling aid for microfluidics systems design and integration is far less mature and presents a significant challenge, thus an opportunity for the microfluidics research community.