Spreading of a viscoelastic drop on a solid substrate

We study the spreading of Newtonian viscous (aqueous glycerin solution) and viscoelastic (aqueous polymer solution) drops on solid substrates with different wettabilities. For drops of the same zero-shear viscosity, we find in the early stages of spreading that viscoelastic drops (i) spread faster a...

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Bibliographic Details
Published in:Journal of fluid mechanics 2024-07, Vol.988, Article A51
Main Authors: Rostami, Peyman, Fricke, Mathis, Schubotz, Simon, Patel, Himanshu, Azizmalayeri, Reza, Auernhammer, Günter K.
Format: Article
Language:English
Subjects:
Contact angle
JFM Papers
Polymers
Relaxation time
Rheology
Shear
Shear rate
Shear thinning (liquids)
Shear viscosity
Spreading
Substrates
Viscoelasticity
Viscosity
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Summary:We study the spreading of Newtonian viscous (aqueous glycerin solution) and viscoelastic (aqueous polymer solution) drops on solid substrates with different wettabilities. For drops of the same zero-shear viscosity, we find in the early stages of spreading that viscoelastic drops (i) spread faster and (ii) their contact radius shows a different power law vs time than Newtonian drops. We argue that the effect of viscoelasticity is only observable for experimental time scales of the order of or larger than the internal relaxation time of the viscoelastic polymer solution. We attribute this behaviour to the shear thinning of the viscoelastic polymer solution. When approaching the contact line, the shear rate increases and the steady-state viscosity of the viscoelastic drop is lower than that of the Newtonian drop. We support our experimental findings with a simple (first-order) perturbation model that qualitatively agrees with our findings.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2024.450