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Optical Manipulation of Liquids by Thermal Marangoni Flow along the Air–Water Interfaces of a Superhydrophobic Surface
[Image: see text] The control of liquid motion on the micrometer scale is important for many liquid transport and biomedical applications. An efficient way to trigger liquid motion is by introducing surface tension gradients on free liquid interfaces leading to the Marangoni effect. However, a prono...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397335/ https://www.ncbi.nlm.nih.gov/pubmed/34256567 http://dx.doi.org/10.1021/acs.langmuir.1c00539 |
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author | Gao, Aiting Butt, Hans-Jürgen Steffen, Werner Schönecker, Clarissa |
author_facet | Gao, Aiting Butt, Hans-Jürgen Steffen, Werner Schönecker, Clarissa |
author_sort | Gao, Aiting |
collection | PubMed |
description | [Image: see text] The control of liquid motion on the micrometer scale is important for many liquid transport and biomedical applications. An efficient way to trigger liquid motion is by introducing surface tension gradients on free liquid interfaces leading to the Marangoni effect. However, a pronounced Marangoni-driven flow generally only occurs at a liquid–air or liquid–liquid interface but not at solid–liquid interfaces. Using superhydrophobic surfaces, the liquid phase stays in the Cassie state (where liquid is only in contact with the tips of the rough surface structure and air is enclosed in the indentations of the roughness) and hence provides the necessary liquid–air interface to trigger evident Marangoni flows. We use light to asymmetrically heat this interface and thereby control liquid motion near superhydrophobic surfaces. By laser scanning confocal microscopy, we determine the velocity distribution evolving through optical excitation. We show that Marangoni flow can be induced optically at structured, air-entrapping superhydrophobic surfaces. Furthermore, by comparison with numerical modeling, we demonstrate that in addition to the Marangoni flow, buoyancy-driven flow occurs. This effect has so far been neglected in similar approaches and models of thermocapillary driven flow at superhydrophobic surfaces. Our work yields insight into the physics of Marangoni flow and can help in designing new contactless, light-driven liquid transport systems, e.g., for liquid pumping or in microfluidic devices. |
format | Online Article Text |
id | pubmed-8397335 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-83973352021-08-31 Optical Manipulation of Liquids by Thermal Marangoni Flow along the Air–Water Interfaces of a Superhydrophobic Surface Gao, Aiting Butt, Hans-Jürgen Steffen, Werner Schönecker, Clarissa Langmuir [Image: see text] The control of liquid motion on the micrometer scale is important for many liquid transport and biomedical applications. An efficient way to trigger liquid motion is by introducing surface tension gradients on free liquid interfaces leading to the Marangoni effect. However, a pronounced Marangoni-driven flow generally only occurs at a liquid–air or liquid–liquid interface but not at solid–liquid interfaces. Using superhydrophobic surfaces, the liquid phase stays in the Cassie state (where liquid is only in contact with the tips of the rough surface structure and air is enclosed in the indentations of the roughness) and hence provides the necessary liquid–air interface to trigger evident Marangoni flows. We use light to asymmetrically heat this interface and thereby control liquid motion near superhydrophobic surfaces. By laser scanning confocal microscopy, we determine the velocity distribution evolving through optical excitation. We show that Marangoni flow can be induced optically at structured, air-entrapping superhydrophobic surfaces. Furthermore, by comparison with numerical modeling, we demonstrate that in addition to the Marangoni flow, buoyancy-driven flow occurs. This effect has so far been neglected in similar approaches and models of thermocapillary driven flow at superhydrophobic surfaces. Our work yields insight into the physics of Marangoni flow and can help in designing new contactless, light-driven liquid transport systems, e.g., for liquid pumping or in microfluidic devices. American Chemical Society 2021-07-14 2021-07-27 /pmc/articles/PMC8397335/ /pubmed/34256567 http://dx.doi.org/10.1021/acs.langmuir.1c00539 Text en © 2021 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Gao, Aiting Butt, Hans-Jürgen Steffen, Werner Schönecker, Clarissa Optical Manipulation of Liquids by Thermal Marangoni Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title | Optical Manipulation of Liquids by Thermal Marangoni
Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title_full | Optical Manipulation of Liquids by Thermal Marangoni
Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title_fullStr | Optical Manipulation of Liquids by Thermal Marangoni
Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title_full_unstemmed | Optical Manipulation of Liquids by Thermal Marangoni
Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title_short | Optical Manipulation of Liquids by Thermal Marangoni
Flow along the Air–Water Interfaces of a Superhydrophobic Surface |
title_sort | optical manipulation of liquids by thermal marangoni
flow along the air–water interfaces of a superhydrophobic surface |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397335/ https://www.ncbi.nlm.nih.gov/pubmed/34256567 http://dx.doi.org/10.1021/acs.langmuir.1c00539 |
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