Origin of the scattering peak in microemulsions

Teubner, Max; Strey, R.

doi:10.1063/1.453006

Cited by 857 publications

(907 citation statements)

References 51 publications

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“…33 To obtain structural information on interconnected cylindrical networks, the Teubner-Strey Model has been applied to fit the microemulsion peak occurring at high volume fraction, that is typical for bicontinuous microemulsions or sponge phases. 34 The fits of the model curves to the observed SAXS data were performed with a nonlinear Levenberg-Marquardt least-squares algorithm. 35 …”

Section: B Small-angle X-ray Scatteringmentioning

confidence: 99%

“…In this case, random surface models come into play that are based on Landau theory. 42,43 Here, we use the phenomenological model proposed by Teubner and Strey in which Gaussian fluctuations of the order parameter field determine the scattering intensity in the vicinity of the peak 34 to estimate the domain size and the correlation length of the structures formed at c s ≥ 0.46. The fits reveal a domain size d of 7.1 nm and 6.4 nm for c s = 0.46 and 0.56, respectively, and a correlation length ≤4.5 nm for both systems.…”

Section: Tubular Reverse Micelles and Interconnected Networkmentioning

confidence: 99%

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Structure and dynamics of water in nanoscopic spheres and tubes

Loop

Ottosson

Lotze

et al. 2014

The Journal of Chemical Physics

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We study the reorientation dynamics of liquid water confined in nanometer-sized reverse micelles of spherical and cylindrical shape. The size and shape of the micelles are characterized in detail using small-angle x-ray scattering, and the reorientation dynamics of the water within the micelles is investigated using GHz dielectric relaxation spectroscopy and polarization-resolved infrared pump-probe spectroscopy on the OD-stretch mode of dilute HDO:H 2 O mixtures. We find that the GHz dielectric response of both the spherical and cylindrical reverse micelles can be well described as a sum of contributions from the surfactant, the water at the inner surface of the reversed micelles, and the water in the core of the micelles. The Debye relaxation time of the core water increases from the bulk value τ H 2 O of 8.2 ± 0.1 ps for the largest reverse micelles with a radius of 3.2 nm to 16.0 ± 0.4 ps for the smallest micelles with a radius of 0.7 nm. For the nano-spheres the dielectric response of the water is approximately ∼6 times smaller than expected from the water volume fraction and the bulk dielectric relaxation of water. We find that the dielectric response of nano-spheres is more attenuated than that of nano-tubes of identical composition (water-surfactant ratio), whereas the reorientation dynamics of the water hydroxyl groups is identical for the two geometries. We attribute the attenuation of the dielectric response compared to bulk water to a local anti-parallel ordering of the molecular dipole moments. The difference in attenuation between nano-spheres and nano-cylinders indicates that the anti-parallel ordering of the water dipoles is more pronounced upon spherical than upon cylindrical nanoconfinement.

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Section: B Small-angle X-ray Scatteringmentioning

confidence: 99%

Section: Tubular Reverse Micelles and Interconnected Networkmentioning

confidence: 99%

Structure and dynamics of water in nanoscopic spheres and tubes

Loop

Ottosson

Lotze

et al. 2014

The Journal of Chemical Physics

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“…To generate matching Gaussian random field (GRF) models we employ the field-field correlation function [44,57] …”

Section: Characteristics Of a Sandstone Samplementioning

confidence: 99%

Characterising the Morphology of Disordered Materials

Arns

Knackstedt

Mecke

2002

Morphology of Condensed Matter

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Abstract. We introduce Minkowski functionals to characterise, reconstruct and discriminate different complex material microstructures, for instance, experimental data sets generated from X-ray computer tomography imaging; samples include a suite of Fontainebleau sandstone, and a heterogeneous cross-bedded sandstone. Three distinct classes of digitised complex microstructure are considered: particle based Boolean models, structures generated by level-cuts through Gaussian fields, and models based on a Voronoi tesselation of space. One can define a set of measures for random composite media from a single image at any phase fraction φ which allows one to accurately reconstruct the medium for all other phase fractions and to predict, for instance, the percolation threshold pc. The evolution of the Minkowski functions during erosion and dilation operations on non-convex morphologies leads to a very accurate discrimination of morphologybetter than commonly used techniques such as structure functions or chord length distributions. Spatial Structures: Experimental Data and Stochastic ModelsThe structure of a disordered material -an oil bearing rock, a piece of paper, or a polymer composite -is a remarkably incoherent concept. Despite this, scientists and engineers are asked to predict the properties of a disordered material based on the "structure" of its constituent components. A major shortcoming in the understanding of processes involving complex materials has been an inability to accurately characterize microstructure. The specification of "structure" requires topological as well as geometric descriptors to characterize the connectivity and the shape of the spatial configuration. In oil recovery from petroleum reservoir rocks, an area of particular interest to the authors, recovery depends crucially on the topology of the pore space and on the mean curvature of the surfaces where immiscible phases meet at a contact angle. To determine accurate flow models and to devise intelligent recovery strategies requires an accurate characterization of reservoir rocks in terms of topology and geometry.To date, the main toolkit used to quantify complex structures has been primarily that of the statistical physicist and not the advanced techniques developed in spatial statistics [11,59]

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“…Small-angle neutron scattering is among the most important experimental techniques to investigate and characterize the structure and dynamics of microemulsions and sponge phases, [11][12][13] to elucidate the role of additives such as amphiphilic block copolymers [14][15][16][17] or non-absorbing polymers, 18,19 and to understand the behavior of unconventional microemulsions containing supercritical CO 2 instead of oil. 20,21 As microemulsions with new components and additives become important for future applications, it is important to understand in more detail which information about the emergent properties of the surfactant membranes can be extracted from a scattering experiment.…”

Section: Introductionmentioning

confidence: 99%

“…32 Since the structure of microemulsions is dominated by the curvature elasticity of the surfactant layer, a crucial step in understanding it is to identify how the scattering peaks follow from the elastic properties of the surfactant membrane. The first theories 11,33,34 were phenomenological theories of the Ginzburg-Landau type. In them, Gaussian fluctuations of the order-parameter field determine the scattering intensity, which is given by the so-called Teubner-Strey formula for bulk scattering.…”

Section: Introductionmentioning

confidence: 99%

Scattering intensity of bicontinuous microemulsions and sponge phases

Peltomäki

Gompper

Kroll

2012

The Journal of Chemical Physics

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Monte Carlo simulations of dynamically triangulated surfaces of variable topology are used to investigate the scattering intensities of bicontinuous microemulsions. The bulk scattering intensity is shown to follow the Teubner-Strey expression. The domain size and the correlation length are extracted from the scattering peaks as a function of the bending rigidity, saddle-splay modulus, and surfactant density. The results are compared to earlier theories based on Ginzburg-Landau and Gaussian random field models. The ratio of the two length scales is shown to be well described by a linear combination of logarithmically renormalized bending rigidity and saddle-splay modulus with universal prefactors. This is in contrast to earlier theoretical predictions in which the scattering intensity is independent of the saddle-splay modulus. The equation of state, and the asymptotics of the bulk and film scattering intensities for high and low wave vectors are determined from simulations and compared with theoretical results.

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Origin of the scattering peak in microemulsions

Cited by 857 publications

References 51 publications

Structure and dynamics of water in nanoscopic spheres and tubes

Structure and dynamics of water in nanoscopic spheres and tubes

Characterising the Morphology of Disordered Materials

Scattering intensity of bicontinuous microemulsions and sponge phases

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