Wormlike Micellar and Vesicular Phases in Aqueous Solutions of Single-Tailed Surfactants with Aromatic Counterions

Microstructure and Dynamics of Wormlike Micellar Solutions Formed by Mixing Cationic and Anionic Surfactants

Small-angle neutron scattering (SANS) and rheology are used to probe the wormlike micelles formed in mixtures of a cationic (cetyl trimethylammonium tosylate, CTAT) and an anionic surfactant (sodium dodecyl benzene sulfonate, SDBS). For a fixed composition of 97/3 CTAT/SDBS, the zero-shear viscosity η0 initially increases rapidly with surfactant concentration, but decreases beyond an intermedia...

Highly Viscoelastic Wormlike Micellar Solutions Formed by Cationic Surfactants with Long Unsaturated Tails

Cationic surfactantshaving long (C22)mono-unsaturated tailswerestudied inaqueoussolutionscontaining salt using steady and dynamic rheology. The surfactant erucyl bis(hydroxyethyl)methylammonium chloride self-assembles into giant wormlike micelles, giving rise to unusually strong viscoelasticity. Under ambient conditions, the viscosity enhancement due to surfactant exceeds a factor of 107. Some ...

Rheology of Surfactants: Wormlike Micelles and Lamellar Liquid Crystalline Phases

Nonlocal effects in flows of wormlike micellar solutions.

The flow curve of wormlike micelles usually exhibits a stress plateau sigma* separating high and low viscosity branches, leading to shear-banded flows. We study the flow of semidilute wormlike micellar systems in a confined geometry: a straight microchannel. We characterize their local rheology thanks to particle image velocimetry. We show that flow curves cannot be described by a simple consti...

Strip waves in vibrated shear-thickening wormlike micellar solutions.

We present an instability in vertically vibrated dilute wormlike micellar solutions. Above a critical driving acceleration the fluid forms elongated solitary domains of high amplitude waves. We model this instability using a Mathieu equation modified to account for the non-Newtonian character of the fluid. We find that our model successfully reproduces the observed transitions.