Microrheology of giant-micelle solutions

• Published in: Europhysics letters Vol. 57; no. 5; pp. 738 - 744
• Main Authors: Cardinaux, F, Cipelletti, L, Scheffold, F, Schurtenberger, P
• Format: Journal Article
• Language: English
• Published: Les Ulis IOP Publishing 01.03.2002; EDP Sciences; EDP sciences
• Subjects: 82.70.Uv; 83.85.Ei; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Viscoelasticity; Micelle; Investigation method; Surfactant; Rheological properties; Concentrated solution
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i2002-00525-0

Optical tracer-microrheology has been applied to study the rheological properties of a concentrated surfactant solution. Under the chosen conditions these surfactants self-assemble to form giant polymer-like micelles, resulting in a strongly viscoelastic liquid. A novel approach to the analysis of the local dynamic properties of tracer particles is presented, based on a combination of single- and multi-speckle diffusing wave spectroscopy (DWS). With this technique we could significantly extend the accessible frequency range to the key rheological properties as given by the loss and storage modulus, $G''(\omega)$ and $G'(\omega)$. A study of the high-frequency range, not accessible to standard techniques, shows good overall agreement with conventional models. However, we find a distinct temperature dependence of the characteristic modulus G0 incompatible with the simple picture of a single relaxation process.