Title

Thermally induced collision of droplets in an immiscible outer fluid

Authors

Authors

A. Davanlou;R. Kumar

Comments

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Abbreviated Journal Title

Sci Rep

Keywords

LIQUID DROPLETS; COALESCENCE; DROPS; MICROFLUIDICS; DISRUPTION; SEPARATION; BUBBLES; PHYSICS; Multidisciplinary Sciences

Abstract

Micro-total analysis systems (mu TAS) have attracted wide attention and are identified as a promising solution for sample transport, filtration, chemical reactions, separation and detection. Despite their popularity, the selection of an appropriate mechanism for droplet transport and coalescence has always been a challenge. This paper investigates the use of Marangoni flow as a mechanism for levitating and transporting droplets on immiscible liquid films at higher speeds than is possible currently. For the first time, we show that it is possible to realize the natural coalescence of droplets through Marangoni effect without any external stimulation, and deliver the coalesced droplet to a certain destination through the use of surface tension gradients. The effects of shape and size on collision outcome are studied. Regions of coalescence and stretching separation of colliding droplets are delineated based on Weber number and impact number. In addition, the effect of viscosity on post collision regimes is studied. The findings in this fundamental study can be beneficial to many applications such as welding, drug delivery and microfluidics devices in controlling small droplets and targeting them to various locations.

Journal Title

Scientific Reports

Volume

5

Publication Date

1-1-2015

Document Type

Article

Language

English

First Page

8

WOS Identifier

WOS:000354106800001

ISSN

2045-2322

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