Design and fabrication of printed electrowetting-on-dielectric device

Due to the expensive price of the fabrication process of the existing semiconductor technology, printing technology has become the center of much attention in research as a micro fabrication technology. Among printing technologies, the rReverse-offset-printing (ROP) method that can achieve high resolution and complicated shape patterns is utilized to fabricate the electrowetting-on-dielectric (EWOD) device, which has been widely researched for the control small-scale droplets. The EWOD device consists of three-layers which were successfully fabricated by the solution-based process. As a metal layer, Ag-ink was printed on the glass substrate by the ROP method. On top of this layer, a polymer solution (polyvinylphenol, PVP) was spin-coated as a dielectric layer, which has a high dielectric strength (100 V/mm) and high dielectric constant (3.9) compared to other spin-coatable dielectric materials. The Teflon solution was spin-coated on top of the dielectric layer to deposit a hydrophobic surface. Using the printed EWOD device, the transport of micro-size droplets was successfully demonstrated.