Modelling X-ray or neutron scattering spectra of lyotropic lamellar phases : interplay between form and structure factors

Nallet, Frédéric; Laversanne, R.; Roux, D.

doi:10.1051/jp2:1993146

Cited by 279 publications

(440 citation statements)

References 10 publications

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“…Similar features have been reported previously in X-ray and neutron scattering spectra from lamellar phases, and have been attributed to modulation of Bragg peak intensities by bilayer form factor effects. 38,45 All of these features were very well described by the head−tail lamellar model, shown in Figure 7 as solid lines. As in the case of the HEA 5 -BA y -C 4 RAFT bilayers, this implies that the BA tails are intercalated with the tails of the opposing membrane.…”

Section: ■ Materials and Methodsmentioning

confidence: 71%

“…HEA 6 -BA 5 -C 4 RAFT SAXS spectra were well-described by fitting to a head−tail lamellar bilayer model using IGOR and an analysis package provided by the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). 36,38 This model calculates the scattered intensity I(q) as…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…36,38 The SLDs of the headgroup, the tail, and the solvent were calculated, and Δρ H and Δρ T were fixed. The model fitting routine is very sensitive to the initial values of the remaining parameters (d, δ H , δ T , η cp ), and these values must also be constrained to physically realistic values.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Phase Behavior of Amphiphilic Diblock Co-oligomers with Nonionic and Ionic Hydrophilic Groups

et al. 2013

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The synthesis of a series of co-oligomer amphiphiles by RAFT and their self-assembly behavior in water is described. These novel amphiphiles, comprised of styrene, butyl acrylate, and alkyl hydrophobes together with ionic acrylic acid and nonionic hydroxyethylacrylate hydrophilic moieties and with a total degree of polymerization from 5 to 17, represent a new class of small-molecule surfactants that can be formed from the immense potential library of all polymerizable monomers. Examples of micellar solutions and discrete cubic, hexagonal, lamellar, and inverted hexagonal lyotropic phases, as well as vesicle dispersions and coexisting lamellar phases, are reported and characterized by small-angle scattering. The variation of self-assembly structure with co-oligomer composition, concentration, and solution conditions is interpreted by analogy with the surfactant packing parameter used for conventional small-molecule amphiphile ABSTRACT: The synthesis of a series of co-oligomer amphiphiles by RAFT and their self-assembly behavior in water is described. These novel amphiphiles, comprised of styrene, butyl acrylate, and alkyl hydrophobes together with ionic acrylic acid and nonionic hydroxyethylacrylate hydrophilic moieties and with a total degree of polymerization from 5 to 17, represent a new class of smallmolecule surfactants that can be formed from the immense potential library of all polymerizable monomers. Examples of micellar solutions and discrete cubic, hexagonal, lamellar, and inverted hexagonal lyotropic phases, as well as vesicle dispersions and coexisting lamellar phases, are reported and characterized by small-angle scattering. The variation of self-assembly structure with co-oligomer composition, concentration, and solution conditions is interpreted by analogy with the surfactant packing parameter used for conventional small-molecule amphiphiles.

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Section: ■ Materials and Methodsmentioning

confidence: 71%

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Phase Behavior of Amphiphilic Diblock Co-oligomers with Nonionic and Ionic Hydrophilic Groups

et al. 2013

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“…We simulated the intensity profile of the SAXS reflections for different configurations of the molecules assembly ( Figure 4) and checked against the experimental patterns. We modelled the structure factor as described in Nallet et al and took into account three possibilities, 18 Figure 4I) single bilayers (dimers of LPC and PA intercalated) composed of two opposed monolayers and a large interlamellar water layer; II) a double bilayer formed such that identical headgroups face each other and III) the double bilayer with the choline and carboxyl head groups facing each other.…”

Section: X-ray Diffraction Pattern Simulationmentioning

confidence: 99%

“…We simulated the scattering patterns from the three models proposed in Figure 4, using the box approximation, 18 aiming to reproduce the relative intensities of the observed reflections ( Figure 2…”

Section: X-ray Diffraction Pattern Simulationmentioning

confidence: 99%

Double-bilayer: a new phase formed by lysophospholipids and the corresponding fatty acid

Funari¹,

Rapp²,

Richter³

2009

Quím. Nova

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Recebido em 23/4/08; aceito em 31/10/08; publicado na web em 6/3/09The product of catalytic activity of the enzyme phospholipase A2, which resembles the core unit of animal toxins, on phospholipids is a 1:1 mixture of lysolipid and fatty acid. This mixture was studied by time-resolved simultaneous small-and wide angle x-ray diffraction over the temperature range from 23 to 53.5°C. An unusually large lamellar structure was observed, with d = 11 nm, contradicting the complex functional dimer model between lysolipid and fatty acid. It can be explained by formation of a "doublebilayer", a new phase consisting of two different bilayers, one formed by lysophospholipid and other by fatty acid, bound together by head group interactions. Its strucutre was confirmed by simulations of the X-ray scattering pattern.

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Flexibility and Structure of Fluid Bilayer Interfaces

Rappolt

Pabst²

2008

Structure and Dynamics of Membranous Interfaces

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Modelling X-ray or neutron scattering spectra of lyotropic lamellar phases : interplay between form and structure factors

Cited by 279 publications

References 10 publications

Phase Behavior of Amphiphilic Diblock Co-oligomers with Nonionic and Ionic Hydrophilic Groups

Phase Behavior of Amphiphilic Diblock Co-oligomers with Nonionic and Ionic Hydrophilic Groups

Double-bilayer: a new phase formed by lysophospholipids and the corresponding fatty acid

Flexibility and Structure of Fluid Bilayer Interfaces

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