抄録
Time-resolved observation by transmission electron microscopy (TEM), viz., in situ TEM, of "same regions" in an oriented amorphous and in an unoriented amorphous i-PS thin films during isothermal crystallization was carried out to elucidate its oriented-crystallization and unoriented crystallization mechanisms, respectively. In situ TEM of an oriented i-PS thin film showed that edge-on lamellae grew perpendicularly to the flowing direction to which the c-axis is parallel, but the number of lamellae stacked in the flowing direction did not increase with increasing crystallization time. On the other hand, in situ TEM of an unoriented i-PS thin film showed that a small sheaf-like structure, which consists of several edge-on lamellae, appeared and then these edge-on lamellae grew to make a binocularly developed two-dimensional spherulite. These results indicate that "central entities" (which have been named by us in this study) in the stacked lamellae form at a first stage of isothermal crystallization, and the length and orientation of the "central entities" have an effect on the resulting crystalline morphology after isothermal crystallization. In addition, by real-time in situ TEM of an unoriented i-PS thin film, the growth of i-PS edge-on lamellae were continuously observed for the first time though the image quality at the present stage was not sufficient to clearly identify individual lamellae.
