Evidence of a sponge-to-lamellar phase transition under shear by X-ray scattering experiments in a Couette cell

The L(3) sponge phase under shear in a Couette cell is totally transformed to a lamellar phase L(alpha) above some critical shear rate (gamma) over dot (c). In situ x-ray scattering and simultaneous light microscopy observations show that the first nuclei of the L(alpha) phase appear at a low critical shear rate (gamma) over dot (a) and that the orientation of the lamellae in the L(alpha) phase tilts over from a so-called "a" orientation to a "c" orientation at (gamma) over dot (c). In the regime with two phases (gamma) over dot (a) and (gamma) over dot (c), the phases are in an epitaxial relationship immediately after the shear is removed.