Akio Uemura

High-resolution electron microscopy of solution-grown crystals of poly (p-phenylene sulphide)

Crystals of poly (p-phenylene sulphide) were obtained from anα-chloronaphthalene solution. The chain axis (the crystalc-axis) was usually normal to the support-film. For these crystals, high-resolution electron microscopic images were taken as the projection of the molecular chains on theab plane along the chain axis. Occasionally it was observed that crystals took different orientations on the support-film for undefined reasons. From such orientations, the high-resolution image of a crystal rotated by 28.7° around thea-axis from the usual orientation, was also obtained.

Iodine Atoms Structured in (SN)x

Electron diffraction pattern of iodinated (SN)x shows that iodine atoms are structured as a chain along the molecular axis of (SN)x. High resolution electron micrograph and its optical transform show that the crystalline lattice is severely distorted by iodination, but the (02) plane is comparatively stable for iodine invasion. Iodine atoms are considered to be settled on the (02) plane, where iodine atoms are structured as iodine chains and the two iodine chains tend to pair.

Microstructural study of as-polymerized and isomerized fibrils of trans-polyacetylene

Abstract Two kinds of trans-polyacetylenes (PA) were prepared for electron microscopy. For sample A, cis-PA was isomerized into trans-PA by annealing at 150°C. For sample B, acetylene was polymerized directly to the trans form at 80°C. Electron diffraction showed that the lattice parameters were larger for sample A than those of sample B, especially the b-axis. The expansion resulted from inclusion of remnant cis units as defects in the trans crystal. A lattice image of sample A revealed that crystallites had a fairly broad orientation distribution within the fibril, which was induced by chain extension by the transformation from cis to trans forms. The crystallite dimension along the polymer chain direction was smaller than that in the lateral direction. Based on this structural information, an intrafibrillar hopping mechanism was proposed for the electrical conduction of the iodine doped PA.