Electrodewetting on Transparent Substrate: Device Fabrication and Demonstration

Electrodewetting [1] is a newly discovered droplet manipulation mechanism that works in a manner opposite to the well-known electrowetting including electrowetting-on-dielectric (EWOD) [2]. When electrically actuated, the contact angle of a liquid on a solid surface would “increase” (i.e., electrodewetting) rather than decrease (i.e., electrowetting). This opposite effect of electrowetting allows digital microfluidic devices to work on a hydrophilic surface, i.e., free of the hydrophobic topcoat that has been the main drawback of electrowetting. In this paper, we detail the design and fabrication of electrodewetting “devices” and advance the technology to accommodate transparent substrates. To prove the feasibility of transparent devices, we achieve moving and splitting aqueous droplets along ITO electrodes on a glass wafer by electrodewetting with only ~5 V. The fabrication process is simple and compatible with today's LCD manufacturing process, indicating potential for low cost.