Fluid Membranes in the Water/NACL — AOT System: A Study Combining Small — Angle Neutron Scattering, Electron Microscopy and NMR Self — Diffusion

Strey, R.; Jahn, Wolfgang; Skouri, M.; Porte, G.; Marignan, J.; Olsson, Ulf

doi:10.1007/978-94-011-2540-6_15

Cited by 20 publications

(34 citation statements)

References 36 publications

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“…A similar phase, the sponge phase, appears in binary systems of water and amphiphile, where now the two labyrinths are occupied by water, which are separated by an amphiphilic bilayer. The pictures obtained by free-fracture microscopy [107] are even more suggestive in this case, because the sample has a preference to break along the bilayer mid-surface, so that the three-dimensional structure of the membrane becomes visible. An example is shown in Fig.…”

Section: Microemulsion and Sponge Phasesmentioning

confidence: 92%

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Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Schwarz

Gompper

2002

Morphology of Condensed Matter

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Amphiphiles are molecules which have both hydrophilic and hydrophobic parts. In water-and/or oil-like solvent, they self-assemble into extended sheet-like structures due to the hydrophobic effect. The free energy of an amphiphilic system can be written as a functional of its interfacial geometry, and phase diagrams can be calculated by comparing the free energies following from different geometries. Here we focus on bicontinuous structures, where one highly convoluted interface spans the whole sample and thereby divides it into two separate labyrinths. The main models for surfaces of this class are triply periodic minimal surfaces, their constant mean curvature and parallel surface companions, and random surfaces. We discuss the geometrical properties of each of these types of surfaces and how they translate into the experimentally observed phase behavior of amphiphilic systems.

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Section: Microemulsion and Sponge Phasesmentioning

confidence: 92%

“…From Ref. [107]. mechanics of membranes, however, is only beginning to emerge in recent years [75,40,78,18,35].…”

Section: Microemulsion and Sponge Phasesmentioning

confidence: 99%

Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Schwarz

Gompper

2002

Morphology of Condensed Matter

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“…In both phases, these characteristic distances scale inversely to the membrane volume fraction (ϕ) according to swelling laws. 8,24 For the cetylpyridinium chloride (CPCl)− hexanol−brine system, 15,27 the L 3 phase exists over a narrow range of hexanol/CPCl ratios but over a large range of membrane volume fractions with passage sizes ranging from nanometers to a few micrometers. Reducing the hexanol concentration moves the system though a narrow two-phase region (L 3 and L α phases) into the large L α phase, which is similarly stable over a wide range of membrane volume fractions.…”

Section: ■ Introductionmentioning

confidence: 99%

“…18−21 The microstructure of the L 3 and L α phases has been probed by X-ray and neutron small-angle scattering (SAS) 8,22−24 and freeze fracture electron microscopy (FFEM). 8,25,26 L 3 FFEM images revealed saddle microstructures with a clear distinction between aqueous solvent and membrane structure, 8,25,26 whereas the L α consists of undulating stacks of bilayers as well as multi-lamellar liposomes and perforated vesicles. 8,25,26 The position of the SAS primary peak reveals the average passage diameter (d 3 ) of the L 3 phase and repeat spacing (d α ) for the L α phase.…”

mentioning

confidence: 97%

“…8,25,26 L 3 FFEM images revealed saddle microstructures with a clear distinction between aqueous solvent and membrane structure, 8,25,26 whereas the L α consists of undulating stacks of bilayers as well as multi-lamellar liposomes and perforated vesicles. 8,25,26 The position of the SAS primary peak reveals the average passage diameter (d 3 ) of the L 3 phase and repeat spacing (d α ) for the L α phase. In both phases, these characteristic distances scale inversely to the membrane volume fraction (ϕ) according to swelling laws.…”

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confidence: 97%

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Amplitude-Modulated Atomic Force Microscopy Reveals the Near Surface Nanostructure of Surfactant Sponge (L₃) and Lamellar (L_α) Phases

Wydro

Warr

2015

Langmuir

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Amplitude-modulated atomic force microscopy (AM-AFM) has been used to study the nanostructure of cetylpyridinium chloride (CPCl)-hexanol-0.2 M NaCl sponge (L3) and lamellar (Lα) phases near a mica surface. For both phases, membrane volume fractions of 22, 27, and 32 vol % were investigated, with the L3 or Lα phase selected by adjusting the co-surfactant/surfactant ratio (hexanol/CPCl). For the L3 phase, the presence of the surface flattens the three-dimensional bulk structure. AM-AFM clearly resolves the membrane and solvent passages in the near surface layer. Increasing the membrane volume fraction decreases the size of the image features because of the lower solvent content. Within error, the average passage sizes in the near surface layer are the same as those in the bulk at the same concentration. Images of the Lα phase reveal undulating near surface sheets. At the highest membrane concentration, the image is very smooth, because the lamellar sheet is confined between the surface and the next near surface layer, which is in close proximity as a result of the low solvent content. As the membrane concentration is reduced, the space between layers is increased and undulations appear in the near surface lamellar structure. Undulations are more pronounced at the lowest membrane volume fraction.

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Structure of Microemulsions Studied by NMR

Lindman

Olsson

1996

Ber Bunsenges Phys Chem

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We discuss the application of NMR to investigate microemulsion structure. There are mainly two important NMR experiments; relaxation and self‐diffusion studies. Of these two, self‐diffusion studies have been found to be particularly informative in that it is the only technique which can demonstrate bicontinuity in equilibrium microemulsions. Self‐diffusion coefficients of water, oil and surfactant can be obtained in the same experiment. For droplet microemulsions, the self‐diffusion coefficients of the surfactant and enclosed solvent correspond to the droplet diffusion coefficient, which in turn depends on its hydrodynamic radius and on interactions. The self‐diffusion coefficient of the continuous solvent is slightly reduced due to obstruction effects, which depends on the droplet shape. For bicontinuous structures, the solvent diffusion on both sides of the surfactant film as well as the surfactant diffusion within the film is monitored. In particular the diffusion of the two solvents depends on how the surfactant film curves. NMR relaxation is found to be useful in the studies of droplet microemulsions. It is very sensitive to the droplet size while at the same time being insensitive to interactions. The latter allows for reliable size information even at higher droplet concentrations.

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Fluid Membranes in the Water/NACL — AOT System: A Study Combining Small — Angle Neutron Scattering, Electron Microscopy and NMR Self — Diffusion

Cited by 20 publications

References 36 publications

Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Amplitude-Modulated Atomic Force Microscopy Reveals the Near Surface Nanostructure of Surfactant Sponge (L₃) and Lamellar (L_α) Phases

Structure of Microemulsions Studied by NMR

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Fluid Membranes in the Water/NACL — AOT System: A Study Combining Small — Angle Neutron Scattering, Electron Microscopy and NMR Self — Diffusion

Cited by 20 publications

References 36 publications

Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Bicontinuous Surfaces in Self-assembling Amphiphilic Systems

Amplitude-Modulated Atomic Force Microscopy Reveals the Near Surface Nanostructure of Surfactant Sponge (L3) and Lamellar (Lα) Phases

Structure of Microemulsions Studied by NMR

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Amplitude-Modulated Atomic Force Microscopy Reveals the Near Surface Nanostructure of Surfactant Sponge (L₃) and Lamellar (L_α) Phases