The WAXS technique is used to determine the degree of
crystallinity of
polymer samples. It can also be used to determine the chemical composition or phase composition of a film, the texture of a
film (preferred alignment of crystallites), the crystallite size and presence of film
stress. As with other diffraction methods, 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 at solids they scatter in predictable patterns based on 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) in the imaginary planes. Every crystalline solid has a unique pattern of d-spacings (known as the powder pattern), which is a fingerprint for that solid. Solids with the same chemical composition but different phases can be identified by their pattern of d-spacings. ==References==