Tank treading and unbinding of deformable vesicles in shear flow: determination of the lift force.
Deformation and tank-treading motion of flaccid vesicles in a linear shear flow close to a wall are quantitatively studied by light microscopy. Velocities of bounded vesicles obey Goldman's law established for rigid spheres. A progressive tilt and a transition of unbinding of vesicles are evidenced upon increasing the shear rate, gamma;. These observations disclose the existence of a viscous lift force, F(l), depending on the viscosity eta of the fluid, the radius R of the vesicle, its distance h from the substrate, and a monotonous decreasing function f(1-v) of the reduced volume v, in the following manner: F(l) = eta(gamma)(R(3)/h)f(1-v). This relation is valid for vesicles both close to and farther from the substrate.
Abkarian
Manouk
M
Laboratoire de Spectrométrie Physique, UMR C5588 (CNRS), Université Joseph Fourier BP87 38402 Saint Martin d'Hères Cedex, France.
Lartigue
Colette
C
Viallat
Annie
A
D055592:Biophysical Phenomena; D001703:Biophysics; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008567:Membranes, Artificial; D008962:Models, Theoretical; D010713:Phosphatidylcholines / Q000737:chemistry*
D008055:Lipids; D008081:Liposomes; D008567:Membranes, Artificial; D010713:Phosphatidylcholines