Instability of a lamellar phase under shear flow: formation of multilamellar vesicles.
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 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 (dgamma;/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.
D000473:Alkanes / Q000737:chemistry; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D008567:Membranes, Artificial; D008853:Microscopy; D000439:Pentanols / Q000737:chemistry; D012542:Scattering, Radiation; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D014867:Water / Q000737:chemistry
D000473:Alkanes; D008081:Liposomes; D008567:Membranes, Artificial; D000439:Pentanols; D014867:Water; C007548:n-dodecane; D012967:Sodium Dodecyl Sulfate