Three-dimensional interior analyses on periodically banded spherulites of poly(dodecamethylene terephthalate)

Most classical crystallization analyses on top surfaces of thin films could not adequately reveal the inner assembly of banded spherulites. Interior dissections by fracturing across various spherulite planes should be conducted to justify the inner lamellar assembly underneath the periodic bands. In this study, self-assembly of poly(dodecamethylene terephthalate) (P12T) into banded spherulites has been explored using powerful microscopy approaches. Results interestingly show a hierarchical ordered sequence of tangentially and radially oriented crystals into alternating polycrystalline layers. The layer width of the inner bands exactly matches with the optical inter-ring spacing (ca. 5 μm), proving emphatically that the interior lamellar assembly accurately accounts for the optical patterns of periodic rings.