The Role of Electric Pressure/Stress Suppressing Pinhole Defect on Coalescence Dynamics of Electrified Droplet SCIE SCOPUS

Cited 2 time in WEB OF SCIENCE Cited 2 time in Scopus
Title
The Role of Electric Pressure/Stress Suppressing Pinhole Defect on Coalescence Dynamics of Electrified Droplet
Author(s)
Lee, Jaehyun; Esmaili, Ehsan; Kang, Giho; Seong, Baekhoon; Kang, Hosung; Kim, Jihoon; Jung, Sunghwan; Kim, Hyunggun; Byun, Doyoung
KIOST Author(s)
Kim, Jihoon(김지훈)
Alternative Author(s)
김지훈
Publication Year
2021-05
Abstract
The dimple occurs by sudden pressure inversion at the droplet's bottom interface when a droplet collides with the same liquid-phase or different solid-phase. The air film entrapped inside the dimple is a critical factor affecting the sequential dynamics after coalescence and causing defects like the pinhole. Meanwhile, in the coalescence dynamics of an electrified droplet, the droplet's bottom interfaces change to a conical shape, and droplet contact the substrate directly without dimple formation. In this work, the mechanism for the dimple's suppression (interfacial change to conical shape) was studied investigating the effect of electric pressure. The electric stress acting on a droplet interface shows the nonlinear electric pressure adding to the uniform droplet pressure. This electric stress locally deforms the droplet's bottom interface to a conical shape and consequentially enables it to overcome the air pressure beneath the droplet. The electric pressure, calculated from numerical tracking for interface and electrostatic simulation, was at least 108 times bigger than the air pressure at the center of the coalescence. This work helps toward understanding the effect of electric stress on droplet coalescence and in the optimization of conditions in solution-based techniques like printing and coating.
ISSN
2079-6412
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/41306
DOI
10.3390/coatings11050503
Bibliographic Citation
COATINGS, v.11, no.5, 2021
Publisher
MDPI
Subject
WATER DROPLETS; SURFACE; IMPACT; FLOW
Keywords
droplet coalescence; spray coating; charged droplet; pinhole defect; air film layer
Type
Article
Language
English
Document Type
Article
Publisher
MDPI
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