Adaptive liquid lens based on electrowetting of two immiscible liquids: a study with numerical simulation and analysis

The present work describes a model simulation study of electrowetting on a dielectric surface (EWOD)-based liquid lens using three distinct insulating liquids, namely, silicone oil, n -hexadecane, and n -tetradecane. The model essentially consists of a cylindrical chamber with a typical inner diameter of 3.0 mm and a height of 1.0 mm coated with two different hydrophobic dielectric surfaces, parylene- C and teflon- AF. With a 21.4 mM KCl solution employed as a conducting liquid, the interfacial layer between the two immiscible liquids was found to be modulated precisely for a critical biasing voltage, V > 90 V, switching the curvature profile from diverging to converging type. Moreover, the effects of applied voltage and dielectric layer thickness on this changeover and focal lengths were discussed for a given set of aforesaid pairs of immiscible liquids. Our simulated results and model analyses provide useful insights on the means of experimental strategies, scope, and limitations towards realization of industrial-grade designs and assets.