Selected area electron diffraction polymers

It has been reported that the electrical conductivity strongly depends on the ordered states of the conductive polymer [86]. In other words, the structural and electronic properties of PPy can be easily modified due to the soft lattices, which are reflected in the crystalline structure of the nanomaterials. Iron oxide nanoparticles were thought to serve as a template for the subsequent PPy matrix formation. Ultrasonic energy has been reported to have a strong capabUity to alter the electronic structure of the polymer or even produce various nanoparticles. Here, the crystalline structure change with the nanocomposite formation was investigated by selected-area electron diffraction (SAED) and dark-field TEM microstructures. 

When homopolymers are crystallized from very dilute solutions, either lozenge-shaped platelets or crystals that possess a dendritic habit are formed. Some typical electron micrographs of the crystals precipitated from dilute solution are shown in Figs. 1.12 and 1.13. The crystal habit that is observed depends on the molecular weight of the polymer and the crystallization conditions, such as the temperature and the nature of the solvent. A very striking feature is that the platelets are only about 100 to 200 A thick. In conjunction with selected-area electron diffraction studies, it is shown that the chains are again preferentially oriented normal, or nearly so, to the basal plane of the platelet. Considering the... 

Figure 8. Selected area electron diffraction patterns of [Ni(CN)2NH3] (polymer)(A)x y and [Ni(CN)2NH3] monomer for polypyrrole showing the crystalline nature or the material. The e-beam is parallel to the [001] direction.

Studies of the Fully Collapsed Monolayer. Collapsed monolayers of all polymers were examined by IR spectroscopy and in most cases by electron diffraction using a Phillips EM300 electron microscope set for selected area diffraction. Viewing of the specimens in the microscope... 

Electron diffraction patterns (selected area and high-resolution diffraction, reflection-diffraction, etc.) can be obtained with a TEM by simple switching from image plane to focal plane. Selected area diffraction (SAD) combined with microscopy is an important supplementary tool to X-ray diffraction in crystal structure analysis (less so for polymers). 

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