Gel-phase vesicles buckle into specific shapes

François Quéméneur (1, 2) , Catherine Quilliet (3) , Magalie Faivre (4) , Annie Viallat (5) , Brigitte Pépin-Donat (1)

1 SPRAM - UMR 5819 - Structures et propriétés d'architectures moléculaire
2 Maret Group / Département de Physique
3 LIPhy - Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères]
4 INL - LOCI - INL - Lab-On-Chip et Instrumentation
5 LAI - Adhésion et Inflammation

Osmotic deflation of giant vesicles in the rippled gel-phase $P_{\beta '}$ gives rise to a large variety of novel faceted shapes. These shapes are also found from a numerical approach by using an elastic surface model. A shape diagram is proposed based on the model that accounts for the vesicle size and ratios of three mechanical constants: in-plane shear elasticity and compressibility (usually neglected) and out-of-plane bending of the membrane. The comparison between experimental and simulated vesicle morphologies reveals that they are governed by a typical elasticity length, of the order of one micron, and must be described with a large Poisson's ratio.

Mots clés: Buckling; thin shells; capsules; spherical shells; elastic surfaces; Föppl-von Karman; folds; extreme deformations; axisymmetric buckling; elasticity; curvature; in-plane compressibility; stretch modulus; bending modulus; thin plate; gaussian curvature; vesicles; gel-phase vesicles; GUV; DMPC; rippled phase; stomatocyte; discocyte; biconcave; facetted

Domaines: Matière Molle [cond-mat.soft]

François Quéméneur, Catherine Quilliet, Magalie Faivre, Annie Viallat, Brigitte Pépin-Donat. Gel-phase vesicles buckle into specific shapes. Physical Review Letters, 2012, 108 (10), pp.108303. ⟨hal-00649424⟩