Optimized cross-slot flow geometry for microfluidic extension rheometry

S.J. Haward, Monica Oliveira, M.A. Alves, G.H. McKinley

Research output: Contribution to journalArticle

63 Citations (Scopus)

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 Wicrit 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 s1 "_ 435 s1) and are also in close agreement with numerical simulations performed by using a finitely extensible nonlinear elastic dumbbell model.
LanguageEnglish
Article number128301
Number of pages5
JournalPhysical Review Letters
Volume109
Issue number12
DOIs
Publication statusPublished - 17 Sep 2012

Fingerprint

flow geometry
slots
birefringence
viscosity
stagnation point
fluids
pressure drop
strands
kinematics
simulation
microscopy
anisotropy
polymers
estimates

Keywords

  • flow geometry
  • microfluidics
  • rheometry
  • polymer solutions
  • anisotropy
  • birefringence
  • cross-flow

Cite this

Haward, S.J. ; Oliveira, Monica ; Alves, M.A. ; McKinley, G.H. / Optimized cross-slot flow geometry for microfluidic extension rheometry. In: Physical Review Letters. 2012 ; Vol. 109, No. 12.
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Optimized cross-slot flow geometry for microfluidic extension rheometry. / Haward, S.J.; Oliveira, Monica; Alves, M.A.; McKinley, G.H.

In: Physical Review Letters, Vol. 109, No. 12, 128301, 17.09.2012.

Research output: Contribution to journalArticle

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