Fabrication and Characterization of Electrowetting on the flexible substrate

Abstract

AbstractThis paper reports the fabrication of and characterization on EWOD(electrowetting-on-dielectric) devices on flexible substrates of interest to the flexible displays and devices. The EWOD devices were fabricated on PET (poly ethylene terephthalate) and PMMA (polymethylmethacrylate) substrates. Au and ITO(indium tin oxide) were used as electrode materials. The wet etching process was developed not to attack plastic flexible substrates. The photo resist was used as an insulator materials in EWOD devices due to the deformation of substrate when oxide layer was deposited on plastic substrate. As a hydrophobic layer, cytop was spin-coated on the photo resist. Wetting tests were done with DI water in air environment. In sessile droplet test, the contact angle of droplet changed from 116◦ to 80◦ under DC power. Threshold voltage was 20 Vdc. The droplet was oscillated under AC power because of the frequency. But the contact angle of droplet was began to change at 30Vac and decrease with the increase of AC power. In droplet transporting test, a droplet(0.2§¡) was started transporting at 20Vac and the transporting speed increased with the increase of AC power. But the droplet transporting was not occurred under DC power because of slower contact angle recovery rate under DC power.