Electrowetting, Electrodewetting, and Electronic Control System for Digital Microfluidics
- Author(s): Li, Jia
- Advisor(s): Kim, Chang-Jin
- et al.
For electrowetting-on-dielectric (EWOD) devices, which are most commonly used for digital (droplet) microfluidics, the reliability issues, such as electric breakdown of the dielectric layer, electric charging of the hydrophobic topcoat, and uniformity of the device surface, make their applications and commercialization much more challenging and expensive than originally anticipated. While trying to overcome the reliability issues of EWOD, we discover a new microscale liquid handling mechanism, which we name “electrodewetting”, that works in a manner opposite to electrowetting. Without the need of dielectric layer or hydrophobic topcoat, electrodewetting is not only free from the reliability issues of EWOD but also much simpler to fabricate. Using only 5 V, we were able to move, split, merge, and generate droplets on an open device configuration in air without using the cover plate or oil environment.
The history of EWOD research and commercialization over the last two decades has shown that a success requires not only proper background and expertise in the science and engineering of EWOD but also adequate resources and facilities for fabricating and operating EWOD devices. Unfortunately, these resources and facilities are not available to most researchers and groups, especially outside engineering. To help EWOD realize its inherent potential and boost the field of digital microfluidics for wide acceptance, in this dissertation we propose and start what we call “cybermanufacturing ecosystem” that will empower the mass, who know little about EWOD design, fabrication, and operation, to utilize digital microfluidics through webservices. The goal of the cybersystem is for a user to design an EWOD device within hours instead of weeks and order their design to be fabricated as an actual device by a foundry service. For testing the EWOD devices, we have developed an electronic control system with which users can not only operate but also debug their EWOD devices.