Shear thickening in dilute solutions of wormlike micelles
Department of Chemistry and Biochemistry, University of
California Los Angeles, CA 90095-1569, USA
Accepted: 25 May 2001
A new mechanism is suggested for shear thickening in dilute solutions of wormlike micelles. According to this mechanism, there is an instability above a critical shear rate, , by which micelles aggregate to form networks of bundles. We examine the first step of this instability by studying the aggregation of two micelles into a paired bundle. The model predicts that is given by the inverse of the time necessary for the two micelles to unbind from each other. The order of magnitude and temperature dependence of the predicted are in good agreement with experimental measurements. In addition, the model provides a natural explanation for the observation of coexistence between the shear-induced structure and a dilute phase at fixed shear stress.
PACS: 83.60.Pq – Time-dependent structure (thixotropy, rheopexy) / 61.25.Hq – Macromolecular and polymer solutions: polymer melts; swelling / 61.20.Qg – Structure of associated liquids: electrolytes, molten salts, etc
© EDP Sciences, 2001