Perfectly alternating ethylene-carbon monoxide copolymer crystallized epitaxially on alkali halides. 1. Morphological observation by TEM

Epitaxial crystallization on the (001) substrate face of NaCl and KI of a p erfectly alternating ethylene-carbon monoxide copolymer (poly(3-oxotrimethy lene); POK) from its nitrobenzene solution has been successfully achieved. Transmission electron microscopy observations reveal that (a) the resulting crystal modification and orientation depend on the substrate and (b) POK c hain stems in the rodlike crystals are parallel to the substrate surface an d perpendicular to the long axis of the rod (namely, the edge-on folded-cha in lamella). For the edge-on lamellae grown on KI, lattice images were succ essfully obtained in which (110) lattice fringes could be clearly identifie d. The length of the lattice fringes, viz., the stem length or crystalline core thickness, is estimated at about 60% of the total thickness of one epi taxially grown POK lamella.