X-ray diffraction pole figure

STEREOPOLE software for the analysis of X ray diffraction pole figures with IDL, I. Salzmann and R. Resel, J. Appl. 

X-ray diffraction pole figure measurements on a poly(vinyl fluoride) film [91]. 

The value of the approach using dichroic ratios coupled with a knowledge of the assignments of peaks is further illustrated by measurements on plain polyethylene films [2]. The production process leads to a rather complex orientation pattern. The molten polymer is extruded as a thin, hollow cylinder, in what may be termed the machine direction. It is simultaneously expanded in a plane perpendicular to the machine direction by the application of internal pressure. Additional variables are the extrusion temperature and the rate at which the blown film has been cooled. The resulting orientation behaviour is best studied by x-ray diffraction pole figure measurements [3,4,5] but the infrared approach provides a relatively simple means for obtaining a useful amount of information, particularly for the behaviour of chains in amorphous regions. 

Small-angle X-ray diffraction pole figures can be collected by a method analogous to conventional wide-angle X-ray diffraction pole figures [50]. 

In more recent work, talc-filled polystyrene compounds, with various filler volume fractions, have been processed by compression moulding and through a variety of slit, capillary, rectangular and annular dies [37]. Particle orientation has been characterised using wide angle X-ray diffraction, then expressed in the form of pole figures, and by scanning electron microscopy. It was concluded that... 

To assess about the quality and purity of the synthesized membranes, several experimental techniques and procedures are available many of those are commonly employed in catalyst characterization. Thus, XRD (x-ray diffraction) analysis of the supported samples is conventionally used to identify the type of zeolite, the proportion of amorphous material and impurities, and the preferential orientation of the crystals (XRD-pole figure). However, for the vast majority of the synthesis procedures described, the XRD spectra of the scrapped membrane or the resulting powder from the liquid phase is supplied to avoid the support contribution. 

Figure 26. (102) X-ray pole figure of the (Tl, Bi)-1223 film used for the X-ray diffraction d-26 spectrum measurement shown in Fig. 25. The four well-developed diffraction positions indicate that a and b axes are aligned.

Abstract. Structural properties of rubrene thin films on cleaved mica (001) surfaces were investigated by optical microscopy and x-ray diffraction. Optical microscopy shows, that the crystallization of rubrene results in formation of spherulites. X-ray specular diffraction reveals polycrystalline and polymorphic nature of rubrene. The pole figure measurements of films prepared at low deposition rates reveal orthorhombic structure and indicate fiber textures with crystallographic planes (121), (131) and (141) preferentially oriented parallel to the substrate surface. High deposition rate thin films in addition show polymorphism, corroborating the existence of the orthorhombic and the triclinic phase. 

For thin specimens it is also possible to perform pole figure measurements in transmission mode [2]. Because of the difficulty of preparing thin specimens with a constant thickness this last mode is not often used today for x ray diffraction. 

There are today standard computer controlled x ray diffraction equipments for pole figure measurements as well as software packages for ODF calculation so that only a general knowledge about texture analysis is usually required of researchers who intend to study the anisotropic behavior of materials. Moreover, many papers have demonstrated how physical or mechanical properties can be calculated in textured materials. This is especially true for cubic metals and alloys and, to a lesser extent, for hexagonal alloys. There remain, therefore, many studies to be undertaken, particularly for non-metallic polycrystalline materials. 

Articles on x-ray diffraction measurements of orientation in this period were concerned with the orientation of cellulosic chains in fibers and in cell walls (29-33). A study of cotton, wood, flax, sisal, hemp, and other cellulosic structures established the occurrence of helically oriented cellulosic materials. Naturally occurring cellulose membranes were also investigated. Simon (32) proposed the use of pole figures, ie, stereographic projection of normals to crystallographic planes, to represent the orientation of the chains of crystalline cellulose (32). The development of uniaxial and uniplanar orientation was described based on the x-ray results. 

Wide angle x-ray diffraction and pole figure analysis... 

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