Alternating vorticity bands in a solution of wormlike micelles.
We report on structural characterization of vorticity bands formed in a wormlike micellar solution by Rheo--small-angle neutron scattering and video imaging experiments. Below a critical shear stress tau{c} in Newtonian and shear-thinning regime, only a minor flow alignment of the micelles is observed. Above tau{c}, in the shear-thickening regime, alternating transparent and turbid bands are formed. Triggered small-angle neutron scattering shows different anisotropic patterns in both bands indicating strongly aligned structures. By high-speed video imaging, we show that such an alignment of micelles does not correspond to a phase of lower viscosity.
Herle
Vishweshwara
V
Institute of Food Science and Nutrition, ETH Zurich, 8092 Zurich, Switzerland.
Kohlbrecher
Joachim
J
Pfister
Bruno
B
Fischer
Peter
P
Windhab
Erich J
EJ