The formation of closed-compact multilamellar vesicles (referred to in the literature as the “onion texture”) obtained upon shearing lamellar phases is studied using small-angle light scattering and cross-polarized microscopy. By varying the shear rate $\dot{\gamma }$, the gap cell $D$, and the smectic distance $d$, we show that: (i) the formation of this structure occurs homogeneously in the cell at a well-defined wave vector $q_i$, via a strain-controlled process, and (ii) the value of $q_i$ varies as $(d\dot{\gamma }/D{)}^{1/3}$. These results strongly suggest that formation of multilamellar vesicles may be monitored by an undulation (buckling) instability of the membranes, as expected from theory.

• Received 18 January 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.148305