Lamellar lyomesophases under shear as studied by deuterium nuclear magnetic resonance

The lamellar phases of two aqueous ethylene oxide surfactants, tetra(ethylene oxide) dodecyl ether and hexa(ethylene oxide) dodecyl ether, have been investigated by deuterium nuclear magnetic resonance spectroscopy during shear. The evolution of the shear-induced NMR line shapes and their dependence on surfactant concentration, shear geometry and shear history is analyzed. Two of three previously described shear-induced states (Diat O, Roux D, Nallet F (1993) J Phys II France 3: 1427–1452), namely the state of aligned lamellae with the layer normal parallel to the velocity gradient, which occurs at low shear rates, and the vesicular state at intermediate shear rates are found and identified by their characteristics NMR line shapes.