Rheochaos and flow instability phenomena in a nonionic lamellar phase
Research output: Contribution to journal › Article
In this study we report on instability phenomena in a solution where shear induces multilamellar vesicles (MLVs) from a lamellar phase. A shear-thickening regime has been observed for hexadecyl tetraethylene glycol ether (C16E4) dissolved in D2O at 40 degrees C. In this regime, unstable temporal viscosity behavior, i.e. periodic oscillations, has been observed at 2, 5 and 10 s(-1). Moreover at a shear rate of 10 s(-1) shear banding manifests itself as the occurrence of transparent and turbid bands stacked along the vorticity direction. We perform time-resolved-rheo-small angle neutron scattering (rheo-SANS) experiments to understand the nature of the viscosity oscillations and spatial-resolved experiments to obtain a structural characterization of vorticity bands.