Jump to main content
Jump to site search

Issue 41, 2015
Previous Article Next Article

Shear banding in entangled polymers in the micron scale gap: a confocal-rheoscopic study

Author affiliations

Abstract

Recent shear experiments in well-entangled polymer solutions demonstrated that interfacial wall slip is the only source of shear rate loss and there is no evidence of shear banding in the micron scale gap. In this work, we experimentally elucidate how molecular parameters such as slip length, b, influence shear inhomogeneity of entangled polybutadiene (PBD) solutions during shear in a small gap H ∼ 50 μm. Simultaneous rheometric and velocimetric measurements are performed on two PBD solutions with the same level of entanglements (Z = 54) in two PBD solvents with molecular weights of 1.5 kg mol−1 and 10 kg mol−1 that possess different levels of shear inhomogeneity (2bmax/H = 17 and 240). For the PBD solution made with a low molecular weight PBD solvent of 1.5 kg mol−1, wall slip is the dominant response within the accessible range of the shear rate, i.e., up to the nominal Weissenberg number (Wi) as high as 290. On the other hand, wall slip is minimized using a high molecular-weight PBD solvent of 10 kg mol−1 so that bulk shear banding is observed to take place in the steady state for Wi > 100. Finally, these findings and previous results are in good agreement with our recently proposed phase diagram in the parameter space of apparent Wi versus 2bmax/H suggesting that shear banding develops across the micron scale gap when the imposed Wi exceeds 2bmax/H [Wang et al., Macromolecules, 2011, 44, 183].

Graphical abstract: Shear banding in entangled polymers in the micron scale gap: a confocal-rheoscopic study

Back to tab navigation

Publication details

The article was received on 09 Jun 2015, accepted on 08 Sep 2015 and first published on 08 Sep 2015


Article type: Paper
DOI: 10.1039/C5SM01429H
Author version
available:
Download author version (PDF)
Citation: Soft Matter, 2015,11, 8058-8068
  • Open access: Creative Commons BY license
  •   Request permissions

    Shear banding in entangled polymers in the micron scale gap: a confocal-rheoscopic study

    P. E. Boukany, S. Wang, S. Ravindranath and L. J. Lee, Soft Matter, 2015, 11, 8058
    DOI: 10.1039/C5SM01429H

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements