Abstract
Stopping droplets from bouncing or splashing after impacting a surface is fundamental in preventing cross-contamination, and the spreading of germs and harmful substances. Here we demonstrate that dielectrowetting can be applied to actively control the dynamics of droplet impact. Moreover, we demonstrate that dielectrowetting can be used to prevent droplet bouncing and suppress splashing. In our experiments, the dielectrowetting effect is produced on a flat substrate by two thin interdigitated electrodes connected to an alternating current potential. Our findings show that the strength of the electric potential can affect the dynamic contact angle and regulate the spreading, splashing and receding dynamics at the right time-scales.
Highlights
Stopping droplets from bouncing or splashing after impacting a surface is fundamental in preventing cross-contamination, and the spreading of germs and harmful substances
Our experiments show that the maximum spreading diameter, the contact time, and splashing depend on the dielectrophoretic force acting on the droplet, which, in turn, is controlled by the amplitude of the applied electric potential
The experiment consists of water droplets impacting a flat Printed Circuit Board (PCB) connected to an alternating current (AC) potential
Summary
Stopping droplets from bouncing or splashing after impacting a surface is fundamental in preventing cross-contamination, and the spreading of germs and harmful substances. Our findings show that the strength of the electric potential can affect the dynamic contact angle and regulate the spreading, splashing and receding dynamics at the right time-scales. The wettability of the substrate, as quantified by the contact angle, is controlled by an electric potential applied between the needle and the flat electrode. In this scenario, wettability changes are the result of the interaction between free ions on the droplet and the polarised solid dielectric layer[9]. Past studies have demonstrated the versatility of both electrowetting and dielectrowetting on controlling the contact angle on static or dynamics systems. For biological structured surfaces, droplet splitting was found to effectively reduce the contact t ime[28]
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