Search results for "Small-Angle Scattering"

Fractal approach in petrology: Combining ultra small angle (USANS), and small angle neutron scattering (SANS)

2000

Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.

Determination of the Composition of Mixed Hydrogenated and Fluorinated Micelles by Small Angle Neutron Scattering

1997

In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

2012

Import JabRef; International audience; Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

Scattering perspectives on nanostructural inhomogeneity in polymer network gels

2017

Abstract Scattering methods based on spatial and temporal contrast fluctuations in polymer-network gels, which originate from polymer-segmental density fluctuations, reveal rich insight into different types and levels of nanostructural inhomogeneity in these soft materials. Complementary contrasting as provided by light, neutron, and X-ray scattering allows such information to be obtained on nano- to micrometer length scales. On top of that, complementary use of static and dynamic scattering methods allows the interplay and effect of these inhomogeneities to be unraveled. This article interrelates a multitude of studies on the application of scattering techniques for analytical assessment o…

Neutron Scattering Studies on the Crystallization of Polymers

1985

Abstract Neutron scattering on mixtures of deuterated and undeuterated molecules offer a new approach for solving long standing problems of the structure of semicrystalline polymers. The various ranges of the amount of the scattering vector q yield different informations. From small angle studies the radius of gyration Rg can be obtained, which does not change markedly by crystallization. The scattering intensity in “the intermediate angle range yields mainly the average distance of the crystalline stems. Experimental results show that not only Rg remains almost constant, but that also the pair distribution function g(r) of the monomer units for r«Rg does not change appreciably during cryst…

Chain conformation and structure in amorphous polymers as revealed by X-ray, neutron, light and electron diffraction

1976

Abstract The physical structure of the melt, the supercooled melt, and the glassy state of amorphous polymers can be characterized by the chain conformation, the local order, and the morphology. The conformation was studied by small-angle neutron scattering. The local order was characterized by pair distribution functions which were derived from electron scattering curves. In addition, model calculations were used to gain information about short-range order. The morphology was studied by means of light scattering (density and anisotropy fluctuations), small-angle X-ray scattering (density fluctuations), and magnetic birefringence measurements (orientational order). Experiments were performe…

Structure and thermodynamics in polymer blends. Neutron scattering measurements on blends of poly(methyl methacrylate) and poly(styrene-co-acrylonitr…

1992

Abstract Neutron scattering on polymer blends of deutero-poly(methyl methacrylate) (D-PMMA) and poly(styrene-co-acrylonitrile) with 19 wt% acrylonitrile (PSAN-19) exhibits excess scattering for scattering vectors Q≲0.2 nm−1 if the volume fraction of D-PMMA is less than 0.5 and greater than 0.05. The range of occurrence and the amount of excess scattering depends to a certain degree on the procedure of sample preparation. If the excess scattering is eliminated by linear extrapolation from large to small Q in the Zimm representation, the residual scattering intensity in the small and intermediate Q-range can be interpreted by the mean field approach of de Gennes with a concentration-dependent…

Preparation and characterization of Pd2Sn nanoparticles

2007

We report a non-aqueous solution preparation of Pd{sub 2}Sn nanoparticles with sizes near 20 nm. The intermetallic compound with the Co{sub 2}Si structure has been characterized using transmission electron microscopy, Rietveld refinement of synchrotron X-ray and neutron powder diffraction, and real-space pair distribution function analysis of high-energy synchrotron X-ray scattering. We also present a description of the electronic structure of this covalent intermetallic using density functional calculations of the electronic structure.

Particle characterization using multiple scattering decorrelation methods: hard-sphere model system

2000

Applying static light scattering experiments, we characterize colloidal particles that are used as model hard-sphere systems in experiments investigating their crystallization kinetics. The particles comprise of a compact core of poly(methyl methacrylate) and short polymer hairs grafted onto the surface. We use a contrast variation procedure to determine the refractive index variation within the particles and observe that one component of the binary mixture used as a solvent penetrates the particles and masks completely the small polymer hairs. Making use of the determined refractive index variation, we obtain the average particle radius and its polydispersity from measurements of the parti…

Fractal approach in petrology: combining ultra small angle, small angle and intermediate angle neutron scattering

2000

Ultra small angle neutron scattering (USANS) instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering (SANS) instruments on one side and optical microscopy on the other side. New fields of investigations are now open and important areas of material science (ceramics, glass fibers, natural materials) and fundamental physics (phase transition, phase separation and critical phenomena) can be studied in bulk samples with an accuracy previously unobtainable owing to a combination of favourable features of the neutron-matter interaction: high penetrability of neutrons, even cold neutr…