Research On Digital Microfluidic Device Based On EWOD

In recent years, the emerging digital microfluidic technology has shown huge development potential and application prospect in chemistry, biology, medicine and other areas because of its advantage of simple structure, saving the sample, ease of integration, wide manipulate range and so on. This dissertation has preliminarily discussed the digital microfluidic technology through the method of theoretical analysis, simulation optimization and experimental verification.Firstly, the dissertation analyzed the advantages and disadvantages of various control method of digital microfluidic system, and then, determined to utilize the theory of electrowetting on dielectric(EWOD) to realize the micro droplet’s driven. Afterwards, the dissertation introduced the principle of EWOD, established its mathematical model and simulated the process of EWOD. Furthermore, the dissertation expounded how to implement the micro droplet’s driven using the theory of EWOD in detail.Secondly, the dissertation developed a mathematic model of the digital microfluidic system, simulated the static and dynamic performance of the system with the use of COMSOL Multiphysics 4.4, obtained the electric potential distribution of the system, analyzed the influence of the parameters such as the thickness of dielectric layer to the digital microfluidic chip, and then proved that the single plate structure was easier to drive the drolet than the double plate sructure. Aferwards, the dissertation simulated the micro droplet’s movement process on the premise of the determined structure and parameters. Thus it provided a reliable guide for the optimization of the chip.Finally, according to the system structure and parameters determined by our simulations, we produced a digital microfluidic chip, using the method of wet etching process to make the ITO drive electrode, using the method of RF magnetron sputtering to deposite the Si O2 dielectric layer, and using CH3(CF2)7(CH2)2Si(OC2H5)3 to produce the hydrophobic layer. We also discussed the key technology and influence factors in the chip production process. Then, we designed and welded control circuit of the digital microfluidic system, and also verified its function. After that, we set up a test platform for digital microfluidic system and realized the transport of micro droplet at the voltage of 40 V. The result verified the correctness of the simulation and the feasibility of digital microfluidic system, and laid a foundation for further research on digital microfluidic technology.