Suppression of droplet pinch-off by early onset of interfacial instability

Lathia, R and Dey Modak, C and Sen, P (2023) Suppression of droplet pinch-off by early onset of interfacial instability. In: Journal of Colloid and Interface Science, 646 . pp. 606-615.

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Abstract

Hypothesis: Interfacial instabilities cause undesirable droplet breakage during impact. Such breakage affects many applications, such as printing, spraying, etc. Particle coating over a droplet can significantly change the impact process and stabilize it against breakage. This work investigates the impact dynamics of particle-coated droplets, which mostly remains unexplored. Experiments: Particle-coated droplets of different mass loading were formed using volume addition. The prepared droplets were impacted on superhydrophobic surfaces, and their dynamics were recorded using a high-speed camera. Findings: We report an intriguing phenomenon where an interfacial fingering instability helps suppress pinch-off in particle-coated droplets. This island of breakage suppression, where the droplet maintains its intactness upon impact, appears in a regime of Weber numbers where bare droplet breakage is inevitable. The onset of fingering instability in particle-coated droplets is observed at much lower impact energy, around two times less than the bare droplet. The instability is characterized and explained using the rim Bond number. The instability suppresses pinch-off because of the higher losses associated with the formation of stable fingers. Such instability can also be seen in dust/pollen-covered surfaces, making it useful in many applications related to cooling, self-cleaning, anti-icing etc. © 2023 Elsevier Inc.

Item Type:	Journal Article
Publication:	Journal of Colloid and Interface Science
Publisher:	Academic Press Inc.
Additional Information:	The copyright for this article belongs to authors.
Keywords:	Coatings; Drop breakup; Hydrophobicity; Stability, Different mass; Droplet fragmentation; Droplets impact; Fingering instabilities; Impact dynamics; Impact process; Interfacial instability; Liquid marble; Particle coatings; Pinchoff, High speed cameras, Article; biological model; cleaning; cooling; dust; energy; hydrophobicity; liquid marble; microfluidics; pollen; surface tension
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	14 Dec 2024 00:28
Last Modified:	14 Dec 2024 00:28
URI:	http://eprints.iisc.ac.in/id/eprint/85431

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