STRUCTURE OF A LYOTROPIC LAMELLAR PHASE UNDER SHEAR

The effect of shear on a lyotropic lamellar phase is studied by the me ans of small-angle light scattering and direct microscopic observation s. We found a complex behavior that can be described by a shear diagra m. This diagram exhibits successively as a function of shear four diff erent steady states. After a transition to a phase of monodisperse mul tilamellar vesicles with no long-range order there is a transition to the same vesicles exhibiting long-range order. At even higher shear ra tes, there is a transition between this ordered population of vesicles of size typically 1 mu m to another ordered state made of vesicles wh ich are much bigger (from 10 to 50 mu m).