Multishell Oblate Spheroid Growth in Poly(trimethylene terephthalate) Banded Spherulites

Unique interior dissection coupled with selective etching techniques for exposing the interiors of poly(trimethylene terephthalate) (PTT) banded spherulites. Three banded PTT spherulite types are present, originating from different nuclei geometries and corresponding to different assemblies of interior lamellae, but all possess similar multishell spheroid layered structures, each with their layer thickness exactly equal to the optical interband spacing. Interior lamellae are alternatingly intersected with mutually perpendicular orientations and clear discontinuity, which evidently disagrees with the conventional models of continuous helical twisting for banding. Interior 3D lamellae assemblies also have been fittingly correlated with top-surface banding patterns.