Wide angle X-ray scattering
- Wide angle X-ray scattering
Wide angle X-ray scattering (WAXS) or Wide angle X-ray diffraction (WAXD) is an X-ray diffraction technique that is often used to determine the crystalline structure of polymers. This technique specifically refers to the analysis of Bragg Peaks scattered to wide angles, which (by Bragg's law) implies that they are caused by sub-nanometer sized structures.
Wide angle x-ray scattering is the same technique as Small-Angle X-ray Scattering (SAXS) only the distance from sample to the detector is shorter and thus diffraction maxima at larger angles are observed.
The technique is a time-honored but a somewhat out-of-favor technique for the determination of degree of crystallinity of polymer samples. A diffraction technique for polycrystalline films where only crystallites diffract which are parallel to the substrate surface. The diffraction pattern generated allows to determine the chemical composition or phase composition of the film, the texture of the film (preferred alignment of crystallites), the crystallite size and presence of film stress. According to this method the sample is scanned in a wide angle X-ray goniometer, and the scattering intensity is plotted as a function of the 2θ angle. X ray diffraction is a non destructive method of characterization of solid materials. When X-rays are directed in solids they will scatter in predictable patterns based upon the internal structure of the solid. A crystalline solid consists of regularly spaced atoms (electrons) that can be described by imaginary planes. The distance between these planes is called the d-spacing. The intensity of the d-space pattern is directly proportional to the number of electrons (atoms) that are found in the imaginary planes. Every crystalline solid will have a unique pattern of d-spacings (known as the powder pattern), which is a “finger print” for that solid. In fact solids with the same chemical composition but different phases can be identified by their pattern of d-spacings.
ee also
* X-ray crystallography
Wikimedia Foundation.
2010.
Look at other dictionaries:
X-ray scattering techniques — are a family of non destructive analytical techniques which reveal information about the crystallographic structure, chemical composition, and physical properties of materials and thin films. These techniques are based on observing the scattered… … Wikipedia
X-ray crystallography — can locate every atom in a zeolite, an aluminosilicate with many important applications, such as water purification. X ray crystallography is a method of determining the arrangement of atoms within a crystal, in which a beam of X rays strikes a… … Wikipedia
Biological small-angle scattering — Small angle scattering is a fundamental method for structure analysis of materials, including biological materials. Small angle scattering allows one to study the structure of a variety of objects such as solutions of biological macromolecules,… … Wikipedia
Small-angle neutron scattering — (SANS) is a laboratory technique, similar to the often complementary techniques of small angle X ray scattering (SAXS) and light scattering. These are particularly useful because of the dramatic increase in forward scattering that occurs at phase … Wikipedia
X-ray — [ 22 December 1895 and presented to Professor Ludwig Zehnder of the Physik Institut, University of Freiburg, on 1 January 1896. The dark oval on the third finger is a shadow produced by her ring. [cite book last = Kevles first =Bettyann Holtzmann … Wikipedia
Ray tracing (graphics) — In computer graphics, ray tracing is a technique for generating an image by tracing the path of light through pixels in an image plane. The technique is capable of producing a very high degree of photorealism; usually higher than that of typical… … Wikipedia
Low-energy ion scattering — LEIS redirects here; for the Hawaiian garland see Lei (Hawaii). Low energy ion scattering spectroscopy (LEIS), sometimes referred to simply as ion scattering spectroscopy (ISS), is a surface sensitive analytical technique used to characterize the … Wikipedia
X-ray spectroscopy — is a gathering name for several spectroscopic techniques for determining the electronic structure of materials by using x ray excitation. X ray emission spectroscopy Karl Manne Georg Siegbahn from Uppsala, Sweden (Nobel Prize 1924), who… … Wikipedia
X-ray astronomy — X rays start at 0.008 nm and extend across the electromagnetic spectrum to 8 nm, over which the Earth s atmosphere is opaque. X ray astronomy is an observational branch of astronomy which deals with the study of X ray observation and detection… … Wikipedia
X-ray reflectivity — sometimes known as X ray Specular Reflectivity, X ray Reflectometry, or XRR for short, is a surface sensitive analytical technique used in chemistry, physics, and materials science to characterize surfaces, thin films and multilayers. [ Holy, V.… … Wikipedia
