Shear-induced formation of vesicles in membrane phases: Kinetics and size selection mechanisms, elasticity versus surface tension

Multilamellar vesicles can be formed upon shearing lamellar phases ${(L}_{\alpha })$ and phase-separated lamellar-sponge ${(L}_{\alpha }{/L}_3)$ mixtures. In the first case, the vesicle volume fraction is always 100% and the vesicle size is monitored by elasticity (“onion textures”). In the second system the vesicle volume fraction can be tuned from 0 to 100% and the mean size results from a balance between capillary and viscous forces (“Taylor droplets”). However, despite these differences, in both systems we show that the formation of vesicles is a strain-controlled process monitored by a universal primary buckling instability of the lamellae.