Optimized Cross-Slot Flow Geometry for Microfluidic Extensional Rheometry
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McKinley_Optimized cross.pdf
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1.24 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Haward, Simon J.
Alves, Manuel A.
McKinley, Gareth H.
Oliveira, Monica S. N.
Date Issued
September 2012
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Haward, Simon J. et al. “Optimized Cross-Slot Flow Geometry for Microfluidic Extensional Rheometry.” Physical Review Letters 109.12 (2012). © 2012 American Physical Society
Version
Final published version
Abstract
A precision-machined cross-slot flow geometry with a shape that has been optimized by numerical simulation of the fluid kinematics is fabricated and used to measure the extensional viscosity of a dilute polymer solution. Full-field birefringence microscopy is used to monitor the evolution and growth of macromolecular anisotropy along the stagnation point streamline, and we observe the formation of a strong and uniform birefringent strand when the dimensionless flow strength exceeds a critical Weissenberg number Wi[subscript crit]≈0.5. Birefringence and bulk pressure drop measurements provide self-consistent estimates of the planar extensional viscosity of the fluid over a wide range of deformation rates (26 s[superscript -1]≤ε˙≤435 s[superscript -1]) and are also in close agreement with numerical simulations performed by using a finitely extensible nonlinear elastic dumbbell model.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.109.128301
