Abstract: The morphological structure of poly(trimethylene terephthalate)(PTT) thin films solution-cast at various temperatures was investigated by using polarized light microscopy and atomic force microscopy techniques. Different morphologies of the PTT films were observed at different crystallization temperatures (T_c). In the temperature range of 363-403 K, banded spherulites occurred. When T_c=413 K, the center location of the spherulite showed banded structure, while the outer region of the spherulite displayed a spherulite structure without ring-band. When T_c≥423 K, the normal non-banded spherulite was found. The main reason for producing the ring-banded spherulite is the effect of residual solvent during the crystallization processs of the solution-cast films. At higher crystallization temperatures(≥423 K), no residual solvent exists during the crystallization of the films since the evaporation rate is higher at higher temperatures. So no banded structure is formed.

Key words: Poly(trimethylene terephthalate), Morphological structure, Ring-banded spherulite