Instabilities of micellar systems under homogeneous and non-homogeneous flow conditions

The rheological behavior of a cetylpyridinium chloride 100 mmol l–1/sodium salicylate 60 mmol l–1 aqueous solution was studied in this work under homogeneous (cone and plate) and non-homogeneous flow conditions (vane-bob and capillary rheometers), respectively. Instabilities consistent with non-mono...

Full description

Saved in:
Bibliographic Details
Published in:Rheologica acta 2003, Vol.42 (1-2), p.56-63
Main Authors: MENDEZ-SANCHEZ, Arturo F, LOPEZ-GONZALEZ, M. Rosario, ROLON-GARRIDO, V. Hugo, PEREZ-GONZALEZ, José, DE VARGAS, Lourdes
Format: Article
Language:English
Subjects:
Aqueous solutions
Boundary conditions
Capillary flow
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Material types
Physics
Rheological measurements
Rheological properties
Rheology
Rheometers
Shear rate
Shear stress
Sodium salicylates
Techniques and apparatus
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The rheological behavior of a cetylpyridinium chloride 100 mmol l–1/sodium salicylate 60 mmol l–1 aqueous solution was studied in this work under homogeneous (cone and plate) and non-homogeneous flow conditions (vane-bob and capillary rheometers), respectively. Instabilities consistent with non-monotonic flow curves were observed in all cases and the solution exhibited similar behavior under the different flow conditions. Hysteresis and the sigmoidal flow curve suggested as characteristic of systems that show constitutive instabilities were observed when running cycles of increasing and decreasing stress or shear rate, respectively. This information, together with a detailed determination of steady states at shear stresses close to the onset of the instabilities, allowed one to show unequivocally that "top and bottom jumping" are the mechanisms to trigger the instabilities in this micellar system. It is shown in addition that there is not a true plateau region in between the "top and bottom jumping". Finally, the flow behavior beyond the upturn seemed to be unstable and was found accompanied by an apparent violation of the no-slip boundary condition.
ISSN:0035-4511
1435-1528
DOI:10.1007/s00397-002-0254-y