The European Physical Journal E

, 36:30

Confined flows of a polymer microgel

Authors

  • Baudouin Geraud
    • Institut Lumière Matière, UMR5306 Université Lyon 1-CNRSUniversité de Lyon
  • Lyderic Bocquet
    • Institut Lumière Matière, UMR5306 Université Lyon 1-CNRSUniversité de Lyon
    • Institut Lumière Matière, UMR5306 Université Lyon 1-CNRSUniversité de Lyon
Regular Article

DOI: 10.1140/epje/i2013-13030-3

Cite this article as:
Geraud, B., Bocquet, L. & Barentin, C. Eur. Phys. J. E (2013) 36: 30. doi:10.1140/epje/i2013-13030-3

Abstract

In this paper, we probe the influence of confinement on the flows of a polymer microgel, namely Carbopol. We compare its bulk rheological behavior, measured with a rheometer and well described by a Hershel-Bulkley law, to velocity profiles measured in rough microchannels, obtained with a particle tracking velocimetry technique. We show a strong disagreement between the bulk prediction for the velocity profiles and the measured ones in the microchannels. Velocity profiles in confined conditions are successfully analyzed within the framework of a non-local fluidity model introduced recently (J. Goyon et al. Nature, 454, 84 (2008)). This allows to determine a cooperativity length ξ, whose order of magnitude compares with the structure size of the microgel. Moreover, we measure flow curves using a rheometer for different gap conditions and also show that this set of data exhibit a strong effect of the confinement on the measured rheological properties. This is again characterized by a typical length of the same order as the cooperativity length scale ξ. We thus evidence confinement effects with two complementary experiments which both give the same typical length for the rearrangements in the flows.

Graphical abstract

https://static-content.springer.com/image/art%3A10.1140%2Fepje%2Fi2013-13030-3/MediaObjects/10189_2013_9845_Figa_HTML.jpg

Keywords

Flowing Matter: Liquids and Complex Fluids

Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2013