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Temperature Gradients Drive Bulk Flow Within Microchannel Lined by Fluid–Fluid Interfaces
Author(s) -
Amador Guillermo J.,
Ren Ziyu,
Tabak Ahmet F.,
Alapan Yunus,
Yasa Oncay,
Sitti Metin
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201900472
Subject(s) - microchannel , microscale chemistry , marangoni effect , surface tension , microfluidics , materials science , fluid dynamics , mechanics , temperature gradient , flow (mathematics) , buoyancy , nanotechnology , thermodynamics , physics , mathematics education , mathematics , quantum mechanics
Surface tension gradients induce Marangoni flow, which may be exploited for fluid transport. At the micrometer scale, these surface‐driven flows can be quite significant. By introducing fluid–fluid interfaces along the walls of microfluidic channels, bulk fluid flows driven by temperature gradients are observed. The temperature dependence of the fluid–fluid interfacial tension appears responsible for these flows. In this report, the design concept for a biocompatible microchannel capable of being powered by solar irradiation is provided. Using microscale particle image velocimetry, a bulk flow generated by apparent surface tension gradients along the walls is observed. The direction of flow relative to the imposed temperature gradient agrees with the expected surface tension gradient. The phenomenon's ability to replace bulky peripherals, like traditional syringe pumps, on a diagnostic microfluidic device that captures and detects leukocyte subpopulations within blood is demonstrated. Such microfluidic devices may be implemented for clinical assays at the point of care without the use of electricity.