Application of interface distribution functions to the evaluation of the small angle x-ray scattering of multicomponent polymer systems

1989 ◽  
Vol 267 (5) ◽  
pp. 389-398 ◽  
Author(s):  
H. W. Fiedel ◽  
W. Wenig
Keyword(s):  
Small Angle ◽  
Distribution Functions ◽  
Polymer Systems ◽  
X Ray ◽  
X Ray Scattering ◽  
Multicomponent Polymer ◽  
Ray Scattering

scholarly journals Phase densities and lamellar morphologies of semicrystalline polyethylenesviaabsolute small-angle X-ray scattering measurements

2015 ◽  
Vol 48 (5) ◽  
pp. 1498-1506 ◽  
Author(s):  
Monika Basiura-Cembala ◽  
Kurt Erlacher ◽  
Jan Skov Pedersen ◽  
Bart Goderis
Keyword(s):  
Amorphous Phase ◽  
Small Angle ◽  
Volume Fraction ◽  
Distribution Functions ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Model Independent ◽  
The Absolute ◽  
Ray Scattering

With the crystalline volume fraction from small-angle X-ray scattering (SAXS) and the density of the crystalline phase from wide-angle X-ray diffraction, the amorphous phase density of two representative polyethylenes was calculated as a function of temperature using the absolute total SAXS scattering power or invariant. The density of the amorphous phase in semicrystalline polyethylene is crystallinity independent and is lower than melt-extrapolated values reported in the literature. Model-independent SAXS-based crystallinity values can be calculated with the aid of the densities of the crystalline and amorphous phase and the absolute SAXS invariant. Such model-independent crystallinity values can be used in SAXS curve-shape analysis procedures to obtain the average thickness of the crystalline and amorphous layers also in the case of non-ideal lamellar semicrystalline polymer morphologies for which the number-average long period cannot be retrieved from the maxima in correlation functions or interface distribution functions.

scholarly journals Structural Analysis of Melt-Spun Polymer-Optical Poly(Methyl Methacrylate) Fibres by Small-Angle X-ray Scattering and Monte-Carlo Simulation

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 779
Author(s):  
Jan Kallweit ◽  
Thomas Vad ◽  
Felix Krooß ◽  
Thomas Gries ◽  
Mohmmed Houri ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Structural Properties ◽  
Small Angle ◽  
Processing Parameters ◽  
Distribution Functions ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Melt Spun ◽  
Ray Scattering

The structural properties, mainly the spatial variation of density and chain interaction, of melt-spun polymer optical fibres (POFs) are investigated by small-angle X-ray scattering (SAXS) and compared to Monte-Carlo polymer simulations. The amorphous PMMA POFs had been subjected to a rapid cooling in a water quench right after extrusion in order to obtain a radial refractive-index profile. Four fibre samples with different processing parameters are investigated and the SAXS data analysed via Guinier approach. Distance-distribution functions from the respective equatorial and meridional SAXS data are computed to extract the fibres’ nanostructures in the equatorial plane and along the fibre axis, respectively. Temperature profiles of the cooling process are simulated for different locations within the fibre and taken as input for Monte-Carlo simulations of the polymer structure. The simulation results agree with the SAXS measurements in terms of the cooling profile’s strong influence on the structural properties of the fibre: slower cooling in the centre of the fibre leads to stronger interchain interaction, but also results in a higher density and more homogenous materials with less optical scattering.

Small-angle X-ray scattering investigation of the micellar and submicellar forms of bovine casein

1989 ◽  
Vol 56 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Helmut Pessen ◽  
Thomas F. Kumosinski ◽  
Harold M. Farrell
Keyword(s):  
Electron Density ◽  
Small Angle ◽  
Distribution Functions ◽  
Spherical Particles ◽  
Scattering Data ◽  
Cross Sectional ◽  
Packing Number ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

SummarySmall-angle X-ray scattering was performed on whole casein under submicellar (Ca2+ removed) and micellar (Ca2+ re-added) conditions. Submicellar scattering curves showed two Gaussian components which were interpreted in terms of a spherical particle with two concentric regions of different electron density, a relatively compact core of higher electron density and a looser shell. Normalized scattering curves and calculated distance distribution functions were consistent with this picture. Micellar scattering data, which can yield only cross-sectional information related to a window of scattered intensities, could be analysed by a sum of three Gaussians with no residual function. The two Gaussians with the lower radii of gyration were again taken to indicate the two concentric regions of different electron density of inhomogeneous spherical particles; the third Gaussian was shown to reflect the packing number of these particles within a cross-sectional portion of the micelle, which was 3:1 for this system. These results are a strong indication that submicellar inhomogeneous particles containing hydrophobically stabilized inner cores exist within the colloidal micelle.

Small-Angle X-Ray Scattering of Polymer Systems

2013 ◽  
pp. 391-407 ◽  
Author(s):  
Carlos A. Avila-Orta ◽  
Francisco J. Medellín-Rodríguez
Keyword(s):  
Small Angle ◽  
Polymer Systems ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Small-Angle X-Ray Scattering Studies on the X-Ray Induced Aggregation of Malate Synthase Computer Simulations and Models

1980 ◽  
Vol 35 (11-12) ◽  
pp. 890-901 ◽  
Author(s):  
Peter Zipper ◽  
Helmut Durchschlag
Keyword(s):  
Cross Section ◽  
Small Angle ◽  
Two Dimensions ◽  
Distribution Functions ◽  
Malate Synthase ◽  
Weighted Averaging ◽  
X Ray ◽  
X Ray Scattering ◽  
Induced Aggregation ◽  
Ray Scattering

Malate synthase undergoes an X-ray induced aggregation which can be monitored in situ by small-angle X-ray scattering; the analysis of scattering curves, taken at subsequent stages of aggregation, has led to the establishment of a tentative model for an aggregation in two dimensions (Zipper and Durchschlag (1980) Rad. and Environm. Biophys., in press). This model was checked by comparison of appropriate theoretical curves with the experi­mental curves. The theoretical scattering curves for this comparison were obtained by weighted averaging over the scattering curves calculated for various species of hypothetical aggregates. Based on the approximation of the unaggregated enzyme particle by an oblate cylinder, the aggregates were assumed to be composed of 2, 3, 4 or 6 of such cylinders, associated side-by-side in one and later on in two linear rows. The weight fractions of the species were chosen so, that an optimum fit of the experimental mean radii of gyration and mean degrees of aggregation was achieved. The distance distribution functions calculated for the model are very similar to the functions derived from the scattering experiment. Cross-section Guinier plots of the scattering curves of the model reveal the occurrence of one and later on of two pseudo cross-section factors similar to those observed in the experimental scattering curves. The pseudo thickness factor of the model of the unaggregated particle is found to be retained in the model curves for all stages of aggregation. From these results it can be concluded that the model for the aggregation process is essentially consistent with the scattering behaviour of the aggregating enzyme. Small differences between the theoretical and experimental curves may be explained by the idealizations of the model. The comparison of theoretical curves for alternative models, assuming aggregation in three dimen­sions, suggests that these models are unlikely, though small amounts of three-dimensional aggregates cannot be ruled out completely.

A Revised O2 Reduction Model in Li-O2 Batteries as Revealed by in Situ Small Angle X-Ray Scattering

2019 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Small Angle ◽  
Wide Angle ◽  
Reduction Mechanism ◽  
Reduction Model ◽  
X Ray ◽  
X Ray Scattering ◽  
O2 Reduction ◽  
Ray Scattering

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>

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