Tap dance of a water droplet

Abstract

Electro-elasto-capillarity (EEC) is a new method of droplet encapsulation controlled by an electric field. In this paper, we report some experiments, for the first time, to realize EEC under a dynamic electric field, showing the progress of electrowetting on a moving substrate. We employ the combined effects of surface tension, elastic force and Coulomb force to manipulate the flexible thin film to encapsulate and release a tiny droplet in a controllable and reversible manner. An alternating current electric field is applied to actuate the droplet and film to vibrate, as if they are dancing to a melody. We measured the frequency of the droplet and the film vibration and found that it was twice the input signal; we also carried out frequency analysis experiments. The frequency-doubling phenomenon can be explained theoretically. Our findings may offer a practical method for drug encapsulation and for the actuation of microelectromechanical system devices.

Aminolysis of polyethylene terephthalate surface along with in situ synthesis and stabilizing ZnO nanoparticles using triethanolamine optimized with response surface methodology

“…All the measured receding contact angle of different samples were 0°, indicating the great hysteresis between the advancing and receding contact angle. This could be arising from the roughness of the surface especially for the ZnO treated sample [32,34,35]. Besides, as water moves forward over previously dry surface but moves backward from previously wet surface, contact angle hysteresis could be occurred [36].…”

Moving contact line problem: Advances and perspectives

“…7(a)), so AC actuated EEC is also called as "Tap dance of water droplet". 29 The frequency doubling effect was observed in this process. By deriving the Lagrangian equation of the system, the theoretical model is set up as…”

“…6(c)), such as PDMS films, micro scale devices or graphene films (in MD simulation). 24 Based on EC, Zhao's group realized the opening of the wrapped droplet by applying an electric field in experiments, 29 and this new phenomenon was termed EEC, 9 which is a controllably encapsulation and release method of tiny droplets. EEC has introduced electric field into the droplet-thin film system, so that the deformation of substrate and droplet can be properly controlled.…”

Studies on Surface Tension Influenced Critical Gap in Cantilever Microstructures

“…Adopting the elasto-capillary model of this work in designing the detachment length of cantilevers against capillary stiction is a more conservative and safer choice. In the future, other capillary actuators like the tap dance of a water droplet using electro-elasto-capillary (EEC) mechanism [21] could consider the critical one-half gap in this work.…”