Dynamics of Electrowetting of a Liquid-Liquid Interface in a Cylindrical Tube

원형관내의 액체-액체 계면에 대한 전기습윤 현상의 동적 거동

The contact angle of a meniscus and a droplet can be controlled by using electrowetting phenomena. We investigated the dynamic aspect of electrowetting for an oil-electrolyte interface formed inside a closed glass tube. A step input voltage is applied and the subsequent motion of the interface is recorded by a high-speed camera. A kind of capillary instability is observed near the three-phase contact line, which could degrade the reliability of device utilizing electrowetting such as electrowetting liquid lens. The dynamics of interface motion for different input voltages and the fluid viscosities are analyzed and discussed based on the experimental results.