ATOMIC-FORCE MICROSCOPY OF ISOTACTIC POLYSTYRENE CRYSTALS

The growth of isotactic polystyrene crystals from a thin melt film is examined by atomic force microscopy. The crystals protrude from the fi lm up to about 100 nm to form a hexagonal spiral with a hollow screw d islocation at the center; the distance between neighboring steps of th e growth spiral is discussed on the basis of the critical nucleus. The entire crystal has collapsed to the substrate. An amorphous layer a f ew nanometers thick covers the surface of the crystal. At the crystal- liquid interface, a concave region about 2 nm deep extends ca. 400 nm.