Anisotropic behaviours of droplets impacting on dielectrowetting substrates. Issue 10 (27th February 2020)

• Record Type: Journal Article
• Authors: Vo, Quoc; Fujita, Yuta; Tagawa, Yoshiyuki; Tran, Tuan
• Is Part Of: Soft matter. Volume 16:Issue 10(2020)
• Page Start: 2621
• Page End: 2628
• Publication Date: 2020-02-27
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c9sm02322d
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Non-uniform electric field generated by interdigitated electrodes on a substrate enhances directional spreading of an impacting droplet on the substrate. Abstract : The spreading of a sessile droplet on a solid substrate is enhanced if a non-uniform electric field is applied at the contact-line region. This so-called dielectrowetting effect holds great potential in controlling the spreading of droplets by varying the strength of the electric field. In this paper, we experimentally and theoretically study the effect of the dielectrowetting on the dynamics of droplets impacting on a solid surface having electrodes to impose the non-uniform electric field to the liquid. We experimentally study the anisotropic behaviours in both the spreading and retracting stages: the droplets spread more but retract with significantly smaller rates in the direction parallel to the electrodes. We provide a theoretical explanation for the spreading enhancement caused by dielectrowetting by decoupling it from inertia-induced spreading. We also theoretically account for the reduction in retraction rate using force balance at the contact line. The theoretical analysis in both the spreading and retracting stages is verified experimentally.