Abstract
Surface nanopatterns of dual ring-banded spherulites in poly(nonamethylene terephthalate) (PNT) were investigated using polarized optical microscopy (POM) and atomic force microscopy (AFM). The surface morphology differs between narrow-spaced single ring bands versus widely spaced double ring bands in spherulites, labeled Type-1 and Type-2, respectively. Ridge and valley consist of two discrete species ranging from nano- to micrometer-sized crystals shaped and oriented differently. Ridges of Type-1 and Type-2 spherulites apparently differ in shapes of the crystal plates. AFM height profile analysis reveals that the ridge of Type-2 ring-banded spherulite is higher than that of Type-1 spherulites. The crystal packing on the ridges and valley of these two types of ring-banded was further compared using high-magnification AFM phase imaging. There exists a transition zone in going from the ridge and valley regions in the Type-2 ring-banded spherulites crystallized at Tc = 75-85 °C; the crystals on the transition zone change gradually in sizes and orientation from those in the ridge to valley. By contrast, Type-1 ring-banded spherulite does not have this kind of transition zone, meaning that crystals in the ridges abruptly submerge into valley in Type-1 ring-banded spherulites. Details of packing of nanosize crystals in forming ridge and valleys of these two ring band types are discussed.
Original language | English |
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Pages (from-to) | 5071-5079 |
Number of pages | 9 |
Journal | Journal of Physical Chemistry B |
Volume | 116 |
Issue number | 16 |
DOIs | |
Publication status | Published - 26 Apr 2012 |
Externally published | Yes |