Rheologica Acta

, Volume 47, Issue 1, pp 63–73

Micron-scale origin of the shear-induced structure in Laponite–poly(ethylene oxide) dispersions

  • John R. de Bruyn
  • Frédéric Pignon
  • Emir Tsabet
  • Albert Magnin
Original Contribution

DOI: 10.1007/s00397-007-0211-x

Cite this article as:
de Bruyn, J.R., Pignon, F., Tsabet, E. et al. Rheol Acta (2008) 47: 63. doi:10.1007/s00397-007-0211-x

Abstract

We study the transient response to simple shear of aqueous dispersions of Laponite clay particles and poly(ethylene oxide) at concentrations for which shear induces structure in the form of a network of polymer–clay bonds. We examine the effects of shear on the structure at the micrometer length scale. Bulk rheometric measurements give the material’s response to step changes in shear rate. We find that a critical value of the shear rate separates two regions with different rheological behaviors. Static small-angle light scattering shows a corresponding qualitative change in the anisotropy of the dispersion under shear at the micron scale. We interpret our results in terms of the effects of shear on the interactions between clay particles and polymer chains and on the aggregation mechanisms in the dispersion.

Keywords

Polymer–clay composites Light scattering yield-stress Stress relaxation Shear-induced structure 

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • John R. de Bruyn
    • 1
    • 2
    • 3
  • Frédéric Pignon
    • 3
  • Emir Tsabet
    • 3
  • Albert Magnin
    • 3
  1. 1.Department of Physics and AstronomyUniversity of Western OntarioLondonCanada
  2. 2.Department of Physics and Physical OceanographyMemorial University of NewfoundlandSt. John’sCanada
  3. 3.Laboratoire de RhéologieUniversité Joseph Fourier Grenoble I, Institut National Polytechnique de Grenoble, CNRS, UMR 5520Grenoble Cedex 9France

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