Cargando…

Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows

Droplet microfluidics provides a versatile tool for measuring interfacial tensions between two immiscible fluids owing to its abilities of fast response, enhanced throughput, portability and easy manipulations of fluid compositions, comparing to conventional techniques. Purely homogeneous extension...

Descripción completa

Detalles Bibliográficos
Autores principales: Lee, Doojin, Shen, Amy Q.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000871/
https://www.ncbi.nlm.nih.gov/pubmed/33800831
http://dx.doi.org/10.3390/mi12030272
_version_ 1783671097495912448
author Lee, Doojin
Shen, Amy Q.
author_facet Lee, Doojin
Shen, Amy Q.
author_sort Lee, Doojin
collection PubMed
description Droplet microfluidics provides a versatile tool for measuring interfacial tensions between two immiscible fluids owing to its abilities of fast response, enhanced throughput, portability and easy manipulations of fluid compositions, comparing to conventional techniques. Purely homogeneous extension in the microfluidic device is desirable to measure the interfacial tension because the flow field enables symmetric droplet deformation along the outflow direction. To do so, we designed a microfluidic device consisting of a droplet production region to first generate emulsion droplets at a flow-focusing area. The droplets are then trapped at a stagnation point in the cross junction area, subsequently being stretched along the outflow direction under the extensional flow. These droplets in the device are either confined or unconfined in the channel walls depending on the channel height, which yields different droplet deformations. To calculate the interfacial tension for confined and unconfined droplet cases, quasi-static 2D Darcy approximation model and quasi-static 3D small deformation model are used. For the confined droplet case under the extensional flow, an effective viscosity of the two immiscible fluids, accounting for the viscosity ratio of continuous and dispersed phases, captures the droplet deformation well. However, the 2D model is limited to the case where the droplet is confined in the channel walls and deforms two-dimensionally. For the unconfined droplet case, the 3D model provides more robust estimates than the 2D model. We demonstrate that both 2D and 3D models provide good interfacial tension measurements under quasi-static extensional flows in comparison with the conventional pendant drop method.
format Online
Article
Text
id pubmed-8000871
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-80008712021-03-28 Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows Lee, Doojin Shen, Amy Q. Micromachines (Basel) Article Droplet microfluidics provides a versatile tool for measuring interfacial tensions between two immiscible fluids owing to its abilities of fast response, enhanced throughput, portability and easy manipulations of fluid compositions, comparing to conventional techniques. Purely homogeneous extension in the microfluidic device is desirable to measure the interfacial tension because the flow field enables symmetric droplet deformation along the outflow direction. To do so, we designed a microfluidic device consisting of a droplet production region to first generate emulsion droplets at a flow-focusing area. The droplets are then trapped at a stagnation point in the cross junction area, subsequently being stretched along the outflow direction under the extensional flow. These droplets in the device are either confined or unconfined in the channel walls depending on the channel height, which yields different droplet deformations. To calculate the interfacial tension for confined and unconfined droplet cases, quasi-static 2D Darcy approximation model and quasi-static 3D small deformation model are used. For the confined droplet case under the extensional flow, an effective viscosity of the two immiscible fluids, accounting for the viscosity ratio of continuous and dispersed phases, captures the droplet deformation well. However, the 2D model is limited to the case where the droplet is confined in the channel walls and deforms two-dimensionally. For the unconfined droplet case, the 3D model provides more robust estimates than the 2D model. We demonstrate that both 2D and 3D models provide good interfacial tension measurements under quasi-static extensional flows in comparison with the conventional pendant drop method. MDPI 2021-03-06 /pmc/articles/PMC8000871/ /pubmed/33800831 http://dx.doi.org/10.3390/mi12030272 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ).
spellingShingle Article
Lee, Doojin
Shen, Amy Q.
Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title_full Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title_fullStr Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title_full_unstemmed Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title_short Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows
title_sort interfacial tension measurements in microfluidic quasi-static extensional flows
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000871/
https://www.ncbi.nlm.nih.gov/pubmed/33800831
http://dx.doi.org/10.3390/mi12030272
work_keys_str_mv AT leedoojin interfacialtensionmeasurementsinmicrofluidicquasistaticextensionalflows
AT shenamyq interfacialtensionmeasurementsinmicrofluidicquasistaticextensionalflows