The Movement Characteristic of Micro Droplet by BZN in EWOD structure

EWOD 구조에서 상유전체 BZN에 의한 micro droplet의 이동 특성

This study is about how to lower the driving voltage that enables to move the micro droplet by the EWOD (Electro Wetting On Dielectric) mechanism. EWOD is well known that it is used ${\mu}-TAS$ digital micro fluidics system. As the device which is fabricated with dielectric layer between electrode and micro droplet is applied voltage, the hydrophobic surface is changed into the hydrophilic surface by electrical property. Therefore, EWOD induces the movement of micro droplet with reducing contact angle of micro droplet. The driving voltage was depended on the dielectric constant of dielectric layer, thus it can be reduced by increase of dielectric constant. Typically, very high voltage ($100V{\sim}$) is used to move the micro droplet. In previous study, we used $Ta_{2}O_{5}$ as the dielectric layer and driving voltage was 23V that reduced 24 percent compared with $SiO_2$. In this study, we used $BZN(Bi_{2}O_{3}ZnO-Nb_{2}O_{5})$ layer which had high dielectric constant. It was operated the just 12V. And micro droplet was moved within Is on 15V. It was reduced the voltage until 35 percents compare with $Ta_{2}O_{5}$ and 50 percents compare with $SiO_2$. The movement of micro droplet within 1s was achieved with BZN (ferroelectrics)just on 15V.