Cylindrical intermediates in a shear-induced lamellar-to-vesicle transition

The mechanism and kinetics of a shear-induced formation of multi-lamellar vesicles in a lyotropic lamellar phase of C 10 E 3 (Triethyleneglycol-decylether) was investigated by rheology and time-resolved small-angle neutron and light scattering (SANS, SALS). Starting from a well-defined, macroscopically oriented lamellar phase, the transition occurs in two steps. First, there is a formation of an intermediate structure oriented in the flow direction which scatters only perpendicular to the flow. This is compatible with long, multi-lamellar cylinders (tubuli). Comparing results from three different shear rates shows that the formation of this intermediate structure is strain controlled. As shear is continued, multilamellar vesicles are formed.