DOI: 10.1140/epje/i2002-10108-y
Flow birefringence, stress optical rule and rheology of four micellar solutions with the same low shear viscosity
J.P. Decruppe1 and A. Ponton21 Laboratoire de Physique des Liquides et Interfaces, Groupe Rhéophysique des Colloïdes, Université de Metz, 1 Bd. F. Arago, 57078 Metz, France
2 Laboratoire de Biorhéologie et d' Hydrodynamique Physico-Chimique, Université de Paris 7, 2, place Jussieu, 75251 Paris, Cedex 05, France
Decruppe@lpli.sciences.univ-metz.fr
(Received 18 November 2002 / Published online: 1 April 2003)
Abstract
The flow birefringence and the rheological properties of
four viscoelastic solutions having nearly the same zero shear
viscosity and subjected to shear flows are investigated in the linear
and non-linear domains. The surfactant used for the samples is the
cetyltrimethylammonium chloride in water at the concentration of
100 mmol/l with an organic salt, the sodium salicylate. The low shear
viscosity curve versus the salt concentration is non-monotonic and has
two maxima separated by a minimum forming four domains in which the
salt concentration is chosen. For the two solutions belonging to the
inner branch, i.e. between the two maxima, a simple Maxwellian
behaviour is observed and shear banding occurs as confirmed by the
flow birefringence pictures. Contrary to the results of
P. Fisher (1996) where the unstable flow regime is restricted to the
first decreasing part of the low shear viscosity curve of a
cetylpyridinium chloride solution, we show that shear banding exits in
a wider domain of the salt concentration.
82.70.Dd - Colloids.
83.85.Cg - Rheological measurements - rheometry.
78.20.Fm - Birefringence.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003
