CRYSTALLIZATION OF SYNDIOTACTIC POLYSTYRENE IN BETA-FORM .1. POSITIONAL IDENTIFICATION OF STACKING-FAULTS IN THE SOLUTION-GROWN SINGLE-CRYSTALS

The locations of the stacking faults in p-form single crystals of synd iotactic polystyrene, which were grown isothermally from a dilute solu tion at temperatures ranging from 150 to 210 degrees C, were identifie d in high-resolution and dark-field (DF) images taken by transmission electron. microscopy, The shift or kink of the (210) lattice fringes, which shows the position of the fault, was directly detected in the hi gh-resolution images. DF images taken using several reflections exhibi ted irregularly spaced striations parallel to the b-axis. Computer sim ulation of DF images based on the structural model of the stacking fau lt well supported the view that each striation corresponds to the posi tion of the fault. The striations extended continuously and were very long, and accordingly, it was proposed that the stacking fault influen ces the attachment of a new polymer stem onto the lateral growth face which is not parallel to the be-plane, resulting in irregular fold-sur faces of the single crystals.