Phase shift effect of double dielectric layers in electrowetting on dielectric microfluidic device

In this report, we theoretically and experimentally show the significance of phase shift across multiple dielectric layers in electrowetting-on-dielectric (EWOD) microfluidic devices upon the use of AC voltage. Although various dielectric materials and combinations of multiple dielectric layers were studied to provide reliable EWOD devices, all previous studies have neglected the effect of frequency of actuation voltage. Our present study, however, clearly shows that dielectric breakdown (thus device failure) and actuation force (thus device performance) are strongly dependent on the frequency. This study of phase-shift effect in EWOD microfluidic device can provide important information so that one can find the optimum operation conditions of EWOD device based on their choice of device architecture and working fluids.