HIGH RESOLUTION ELECTRON MICROSCOPY OF THIN CRYSTALLINE FILMS OF ISOTACTIC POLYSTYRENE

Abstract

Crystalline thin films of isotactic polystyrene (i-PS) were produced from their amorphous state by annealing. In the film annealed at 161°C for 7 minutes, crystalline lamellae are set in the edge-on position. A high-resolution electron microscopic image of the specimen showed the (300) lattice fringe (0.63nm) in a narrow band about 6nm wide. This width corresponds to the thickness of crystalline core in a lamella. A high-resolution image of the specimen annealed at 170°C for 2 hours revealed (hk0) lattice fringes, as is the case with a single crystal. This directly demonstrates the existence of single-crystal-like lamella in the flat-on position. In the case of stretched thin film of high molecular weight i-PS which shows a typical fiber pattern on the electron diffraction pattern, the (110) lattice fringe (1.1nm) appeared in the long, slender region along the fiber axis This region seems to be ascribed to the “shish” crystal.