Physics of Fluids - Publications

Flow-induced dissolution of femtoliter surface droplet arrays

arΧiv
Lab on a Chip 18, 1066–1074 (2018)

Authors

	Lei Bao
	Vamsi Spandan
	Yantao Yang
	Brendan Dyett
	Roberto Verzicco
	Detlef Lohse
	Xuehua Zhang

BibTeΧ

@Article{C7LC01321C,
author ="Bao, Lei and Spandan, Vamsi and Yang, Yantao and Dyett, Brendan and Verzicco, Roberto and Lohse, Detlef and Zhang, Xuehua",
title  ="Flow-induced dissolution of femtoliter surface droplet arrays",
journal  ="Lab Chip",
year  ="2018",
volume  ="18",
issue  ="7",
pages  ="1066-1074",
publisher  ="The Royal Society of Chemistry",
doi  ="10.1039/C7LC01321C",
url  ="http://dx.doi.org/10.1039/C7LC01321C",
abstract  ="The dissolution of liquid nanodroplets is a crucial step in many applied processes{,} such as separation and dispersion in the food industry{,} crystal formation of pharmaceutical products{,} concentrating and analysis in medical diagnosis{,} and drug delivery in aerosols. In this work{,} using both experiments and numerical simulations{,} we quantitatively study the dissolution dynamics of femtoliter surface droplets in a highly ordered array under a uniform flow. Our results show that the dissolution of femtoliter droplets strongly depends on their spatial positions relative to the flow direction{,} drop-to-drop spacing in the array{,} and the imposed flow rate. In some particular cases{,} the droplet at the edge of the array can dissolve about 30% faster than the ones located near the centre. The dissolution rate of the droplet increases by 60% as the inter-droplet spacing is increased from 2.5 [small mu ]m to 20 [small mu ]m. Moreover{,} the droplets close to the front of the flow commence to shrink earlier than those droplets in the center of the array. The average dissolution rate is faster for the faster flow. As a result{,} the dissolution time (Ti) decreases with the Reynolds number (Re) of the flow as Ti [is proportional to] Re-3/4. The experimental results are in good agreement with the numerical simulations where the advection-diffusion equation for the concentration field is solved and the concentration gradient on the surface of the drop is computed. The findings suggest potential approaches to manipulate nanodroplet sizes in droplet arrays simply by dissolution controlled by an external flow. The obtained droplets with varying curvatures may serve as templates for generating multifocal microlenses in one array."}