Study of PDMS as Dielectric Layer in Electrowetting Devices

Abstract

An electrowetting-on-dielectric (EWOD) device by using Polydimethylsiloxane (PDMS) as dielectric layer has been fabricated. Aluminium metal film is used for EWOD electrode fabrication. Teflon AF 1600 thin film is coated to improve hydrophobicity and reduce liquid sticking (found in PDMS surface). Both PDMS and Teflon layer is deposited by spin coating. Direct coating of Teflon, on top of PDMS layer, results in poor quality film, because of inherent hydrophobic nature of PDMS. So, Oxygen plasma treatment of PDMS surface is carried, before Teflon coating. Movement of water droplet (conductivity: 250 μ S/m) is obtained at 150 V DC voltage supply. Present study demonstrates a simple, cost and time effective fabrication procedure for EWOD device.