Synchrotron Small Angle X-ray Scattering Study of Melt Crystallized Polymers

1999 ◽  
Vol 590 ◽  
Author(s):  
Georgi Georgiev ◽  
Patrick Shuanghua Dai ◽  
Elizabeth Oyebode ◽  
Peggy Cebe ◽  
Malcolm Capel
Keyword(s):  
Small Angle ◽  
Structural Model ◽  
Structural Parameters ◽  
Lamellar Thickness ◽  
Melt Crystallization ◽  
Two Phase ◽  
X Ray ◽  
Density Correlation ◽  
X Ray Scattering ◽  
Ray Scattering

ABSTRACTIn this paper we report a synchrotron small angle x-ray scattering (SAXS) study of development of structure in semicrystalline Poly(Ether Ether Ketone), (PEEK) and an 80/20 blend with amorphous Poly(Ether Imide) (PEEK/PEI). Samples were treated to dual stage melt crystallization scheme involving initial isothermal crystallization at T1 followed by a second isothermal period at T2 (T1 < T2). Intensity of small angle scattering was measured in real-time. Structural parameters characterizing the lamellar thickness, 1c, long period, L, and SAXS invariant were deduced from the one-dimensional electron density correlation function assuming an ideal, two-phase structural model.

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

Critical region and metal–nonmetal transition in expanded fluid mercury: advanced evaluation of small-angle X-ray scattering data

2010 ◽  
Vol 43 (2) ◽  
pp. 244-249 ◽  
Author(s):  
Wilhelm Ruland ◽  
Friedrich Hensel
Keyword(s):  
Small Angle ◽  
Critical Region ◽  
Structural Model ◽  
Volume Fraction ◽  
Critical Density ◽  
Scattering Data ◽  
Two Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The small-angle X-ray scattering data of expanded fluid mercury published in the literature were evaluated using a modified form of the Teubner–Strey equation for microemulsions together with the general treatment of two-phase systems according to Porod. The parameters obtained in the critical region and the metal–nonmetal (M–NM) transition are evidence of a nanoemulsion composed of M and NM domains. The structure of this emulsion is characterized by density, volume fraction and size parameters (average chord length, polydispersity) of the domains. On the basis of these parameters, a structural model for fluid mercury in the liquid–vapour critical region and the M–NM transition is developed. Analysis of the relationship between the volume fraction of the M domains and the electrical conductivity reveals that a percolation transition occurs, with a threshold located near the liquid–vapour critical density. This observation is consistent with recent theoretical developments.

scholarly journals Determination of nanostructure of liposomes containing two model drugs by X-ray scattering from a synchrotron source

2013 ◽  
Vol 20 (5) ◽  
pp. 721-728 ◽  
Author(s):  
Alexandr Nasedkin ◽  
Jan Davidsson ◽  
Mont Kumpugdee-Vollrath
Keyword(s):  
Experimental Data ◽  
Small Angle ◽  
Structural Parameters ◽  
Water Layer ◽  
Synchrotron Source ◽  
X Ray ◽  
X Ray Scattering ◽  
Extract Information ◽  
Ray Scattering

Small-angle X-ray scattering has been employed to study how the introduction of paracetamol and acetylsalicylic acid into a liposome bilayer system affects the system's nanostructure. An X-ray scattering model, developed for multilamellar liposome systems [Pabstet al.(2000),Phys. Rev. E,62, 4000–4009], has been used to fit the experimental data and to extract information on how structural parameters, such as the number and thickness of the bilayers of the liposomes, thickness of the water layer in between the bilayers, size and volume of the head and tail groups, are affected by the drugs and their concentration. Even though the experimental data reveal a complicated picture of the drug–bilayer interaction, they clearly show a correlation between nanostructure, drug and concentration in some aspects. The localization of the drugs in the bilayers is discussed.

Influence of polychromaticity on particle structure determination in small-angle X-ray scattering

2015 ◽  
Vol 48 (6) ◽  
pp. 1935-1942 ◽  
Author(s):  
Wenjia Wang ◽  
Eleonora V. Shtykova ◽  
Vladimir V. Volkov ◽  
Guangcai Chang ◽  
Lianhui Zhang ◽  
...  
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Shape Reconstruction ◽  
The Body ◽  
Particle Structure ◽  
Saxs Data ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Pink beams are now widely used for small-angle X-ray scattering (SAXS) data collection owing to their high intensity. However, the wavelength spread of a pink beam is a factor of 100 higher than that of a monochromatic beam, thus causing the experimental data to be smeared. To reveal the influence of polychromaticity on shape reconstruction, four geometric bodies (sphere, cube, helix and long cylinder) were used for SAXS data analysis. The results reveal that the influence of polychromaticity on the process of shape reconstruction is significantly more dependent on the geometry of the body than on its size. Scattering objects with smoothed scattering curves can tolerate a higher wavelength spread than those with tortuous curves. It is further demonstrated that the structural parameters calculated from the smeared data sets have little deviation from the ideal ones, which indicates the possibility of using a light source with a greater wavelength spread than a conventional pink beam for special time-resolved SAXS experiments. Finally, it is concluded that SAXS data collected in pink-beam mode can be used directly for structural calculations and model reconstructions without a desmearing procedure.

Small-angle X-ray scattering of two-phase systems: significance of polydispersity

2010 ◽  
Vol 43 (5) ◽  
pp. 998-1004 ◽  
Author(s):  
Wilhelm Ruland
Keyword(s):  
Size Distribution ◽  
Small Angle ◽  
Two Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Phase Systems ◽  
Two Phases ◽  
The Relationship ◽  
Ray Scattering

Evaluation of the small-angle X-ray scattering of two-phase systems leads to the determination of the Porod lengthlpand the correlation lengthlc. In dilute systems, the parameter κl=lc/lp− 1 is a measure of the polydispersity of the chord lengthslwithin the dilute phase, which depends on the size distribution and the shape of the particles forming this phase. As an example, the change of κlwith the size distribution is calculated for spheres and spheroids. For dense two-phase systems, κldepends not only on the polydispersities of the chord lengthsl1andl2of the two phases but also on the spatial order in the system. This is demonstrated by examples related to microemulsions. The appendix contains a short discussion on the relationship between chord-length distributions and Bertrand's paradox.

scholarly journals Domain Organization in Plant Blue-Light Receptor Phototropin2 of Arabidopsis thaliana Studied by Small-Angle X-ray Scattering

2020 ◽  
Vol 21 (18) ◽  
pp. 6638
Author(s):  
Masayoshi Nakasako ◽  
Mao Oide ◽  
Yuki Takayama ◽  
Tomotaka Oroguchi ◽  
Koji Okajima
Keyword(s):  
Blue Light ◽  
Small Angle ◽  
Structural Changes ◽  
Structural Parameters ◽  
Kinase Domain ◽  
Full Length ◽  
Receptor Protein ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Phototropin2 (phot2) is a blue-light (BL) receptor protein that regulates the BL-dependent activities of plants for efficient photosynthesis. Phot2 is composed of two light-oxygen-voltage sensing domains (LOV1 and LOV2) to absorb BL, and a kinase domain. Photo-activated LOV domains, especially LOV2, play a major role in photo-dependent increase in the phosphorylation activity of the kinase domain. The atomic details of the overall structure of phot2 and the intramolecular mechanism to convert BL energy to a phosphorylation signal remain unknown. We performed structural studies on the LOV fragments LOV1, LOV2, LOV2-linker, and LOV2-kinase, and full-length phot2, using small-angle X-ray scattering (SAXS). The aim of the study was to understand structural changes under BL irradiation and discuss the molecular mechanism that enhance the phosphorylation activity under BL. SAXS is a suitable technique for visualizing molecular structures of proteins in solution at low resolution and is advantageous for monitoring their structural changes in the presence of external physical and/or chemical stimuli. Structural parameters and molecular models of the recombinant specimens were obtained from SAXS profiles in the dark, under BL irradiation, and after dark reversion. LOV1, LOV2, and LOV2-linker fragments displayed minimal structural changes. However, BL-induced rearrangements of functional domains were noted for LOV2-kinase and full-length phot2. Based on the molecular model together with the absorption measurements and biochemical assays, we discuss the intramolecular interactions and domain motions necessary for BL-enhanced phosphorylation activity of phot2.

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