Evaluation of Cyanoethyl Pullulan material as the dielectric layer for EWOD devices

Abstract

The excellent dielectric and electrowetting properties of Cyanoethyl Pullulan (CEP) material were evaluated in this paper. The CEP can obtained a dielectric constant of 18 (100 kHz) by spin-coating and annealing at 100 ºC in atmosphere. The asymmetry, reversibility and stability of electrowetting on CEP were studied, showing negative-potential sensitive and good electrowetting performance. Based on these results, an EWOD device with 1 m thick CEP dielectric layer has been fabricated and tested, demonstrating the successful manipulation of water droplets with drive voltage of 20 V. The easy fabrication and excellent performance of CEP make it a superior dielectric material in the future EWOD devices.

Using Ferroelectric Thin Film as the Dielectric for Electrowetting-on-Dielectric

“…ε 0 (8.85*10 −12 F/m), ε is the dielectric constant, and t is the thickness of the dielectric layer. [9] As we can see in the Eq.1, to decrease the driving voltage with reaching the same actuation effect, the electrowetting ability of a droplet is highly dependent on the electrical properties of the dielectric. Therefore, an appropriate dielectric material layer with a high dielectric constant and a small thickness need to be used.…”