Langmuir, Vol.26, No.20, 16178-16185, 2010
Charge-Coupled Transient Model for Electrowetting
Electrowetting is widely used as a means to increase the wettability of droplets on a substrate covered by a dielectric. Although static or quasi-static models of the triple-line movement already exist, little research has been published on transient modeling coupled to the charge transient. This work describes a model of two differential equations coupling the charging to the movement taking into account friction. The model results are validated by comparison to published experimental results. The model focuses on applications, and hence the time to respond, the power consumption, and the energy and its breakdown into components are calculated. Moreover, the use of a generalized voltage source allows us to model successfully the results of a "corona charge" experiment as a means to increase wettability without contact between the electrode and the liquid sample. Finally, the model is extended to an ideal "charge-driven mode" electrowetting proposal resulting in better controllability of the speed and transient time between two contact angle values with applications to lab-on-a chip or displays.