Vortex flow in free-standing smectic C films driven by elastic distortions

Harth, Kirsten; Eremin, Alexey; Stannarius, Ralf

doi:10.1039/c0sm01040e

Cited by 15 publications

(9 citation statements)

References 50 publications

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“…The rosette shaped gel domains have a vortex-like texture around a central topological defect; , for an example see Figure b. The texture and defects are similar to those observed for liquid crystals in the smectic-C phase − …”

Section: Introductionsupporting

confidence: 63%

Slow Relaxation of Shape and Orientational Texture in Membrane Gel Domains

et al. 2015

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Gel domains in lipid bilayers are structurally more complex than fluid domains. Growth dynamics can lead to noncircular domains with a heterogeneous orientational texture. Most model membrane studies involving gel domain morphology and lateral organization assume the domains to be static. Here we show that rosette shaped gel domains, with heterogeneous orientational texture and a central topological defect, after early stage growth, undergo slow relaxation. On a time scale of days to weeks domains converge to circular shapes and approach uniform texture. 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) enriched gel domains are grown by cooling 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):DPPC bilayers into the solid-liquid phase coexistence region and are visualized with fluorescence microscopy. The relaxation of individual domains is quantified through image analysis of time-lapse image series. We find a shape relaxation mechanism which is inconsistent with Ostwald ripening and coalescence as observed in membrane systems with coexisting liquid phases. Moreover, domain texture changes in parallel with the changes in domain shape, and selective melting and growth of particular subdomains cause the texture to become more uniform. We propose a relaxation mechanism based on relocation of lipids from high-energy lattice positions, through evaporation-condensation and edge diffusion, to low-energy positions. The relaxation process is modified significantly by binding Shiga toxin, a bacterial toxin from Shigella dysenteriae, to the membrane surface. Binding alters the equilibrium shape of the gel domains from circular to eroded rosettes with disjointed subdomains. This observation may be explained by edge diffusion while evaporation-condensation is restricted, and it provides further support for the proposed overall relaxation mechanism.

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Section: Introductionsupporting

confidence: 63%

Slow Relaxation of Shape and Orientational Texture in Membrane Gel Domains

et al. 2015

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“…Even though smectic films are less prevalent than soap films, they have many features in common, and they are in many respects much better suited to the investigation of the dynamics of thin freely suspended fluid layers. For example, the use of smectic FSFs facilitates the study of the coupling between director and flow fields in quasi-2D fluids [10,11] and of the formation of spontaneous patterns. They are not subject to drainage or evaporation (at ambient temperatures) and air humidity is not critical.…”

Section: Thin Fluid Filmsmentioning

confidence: 99%

“…The investigation of these films has been focused mainly on director textures, electrical switching processes, optical characteristics and phase transitions, [4][5][6][7][8][9] where these films are a rich source of unique phenomena. For example, the use of smectic FSFs facilitates the study of the coupling between director and flow fields in quasi-2D fluids [10,11] and of the formation of spontaneous patterns. [12] Of particular interest is the investigation of the dynamics of inclusions in such films, [13] which allows the elucidation of details of the dynamics of 2D fluids and membranes.…”

Section: Thin Fluid Filmsmentioning

confidence: 99%

Freely Floating Smectic Films

et al. 2014

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We have investigated the dynamics of freely floating smectic bubbles using high-speed optical imaging. Bubbles in the size range from a few hundred micrometers to several centimeters were prepared from collapsing catenoids. They represent ideal model systems for the study of thin-film fluid dynamics under well-controlled conditions. Owing to the internal smectic layer structure, the bubbles combine features of both soap films and vesicles in their unique shape dynamics. From a strongly elongated initial shape after pinch-off, they relax towards the spherical equilibrium, first by a slow redistribution of the smectic layers, and finally by weak, damped shape oscillations. In addition, we describe the rupture of freely floating smectic bubbles, and the formation and stability of smectic filaments.

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“…In contrast, for a free-standing liquid film there is no shear-stress at both liquid-air interfaces which modifies the boundary conditions and results in a different phenomenology [1]. These boundary conditions can arise in a variety of situations such as biological membranes [3], soap films [4][5][6][7][8][9], liquid-crystal films [10][11][12], fragmentation processes [13], or energy-harvesting technologies [14].…”

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confidence: 99%

Symmetrization of Thin Free-Standing Liquid Films via Capillary-Driven Flow

Bertin,

Niven,

Stone

et al. 2019

Preprint

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We present experiments to study the relaxation of a nano-scale cylindrical perturbation at one of the two interfaces of a thin viscous free-standing polymeric film. Driven by capillarity, the film flows and evolves towards equilibrium by first symmetrizing the perturbation between the two interfaces, and eventually broadening the perturbation. A full-Stokes hydrodynamic model is presented which accounts for both the vertical and lateral flows, and which highlights the symmetry in the system. The symmetrization time is found to depend on the membrane thickness, surface tension, and viscosity.

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Vortex flow in free-standing smectic C films driven by elastic distortions

Cited by 15 publications

References 50 publications

Slow Relaxation of Shape and Orientational Texture in Membrane Gel Domains

Slow Relaxation of Shape and Orientational Texture in Membrane Gel Domains

Freely Floating Smectic Films

Symmetrization of Thin Free-Standing Liquid Films via Capillary-Driven Flow

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