A TEM STUDY ON POLYOXYMETHYLENE RODLIKE CRYSTALS GROWN EPITAXIALLY ONNACL

Rodlike crystals of polyoxymethylene (POM) were isothermally grown ont o the newly cleaved (001) face of NaCl from a 0.1 wt% solution in nitr obenzene and then were studied by transmission electron microscopy (TE M). Morphological observation in bright-and dark-field imaging modes a nd selected-area electron diffraction analysis directly evidenced that POM chain stems in the rodlike crystals are set parallel to the subst rate surface and also perpendicular to the rod axis. That is, each of the rodlike crystals is an ''edge-on'' lamella of POM, the lateral fac e of which is in contact with the substrate surface. The contact plane of the edge-on lamella in question, namely, the crystallographic plan e parallel to the substrate surface, is determined as the (100) plane of the hexagonal crystal lattice of POM.