Single Crystals Self‐Assembled to Sector‐Face Dendritic Aggregates by Synchrotron Microbeam X‐Ray Analysis on Poly(ethylene succinate)

Abstract

Poly(ethylene succinate) (PESu), upon crystallization with a morphology-modulating diluent and at low degree of supercooling, forms peculiarly novel sector-face dendritic aggregates. Delicate dissection by various microscopic techniques is used to confirm the unique differences of these two faces in the PESu dendrites. Powerful synchrotron-source generated X-ray microbeam analysis is performed to prove without doubt the nature of the single crystals that self-assemble into these two sectors, respectively. Both microscopy results and 1D/2D wide-angle X-ray patterns collectively confirm that one sector-face of the PESu dendrites is composed all fully flat-on with the single-crystal's basal face contacting the substrate and branching growth with mutual perpendicular ≈90 °angle intersections; the second face is composed fully edge-on with the prism face contacting the substrate and growth with mutual oblique 5-30 °angle intersections. The growth intersection angles are also proved by the azimuthal angles in 1D and 2D X-ray patterns.

Thermo-Sensitive Poly(p-dioxanone) Banded Spherulites with Controllable Patterns for Iridescence

“…Crystal structure, growth rate, and crystallization temperature may cause a morphological transition. In the case of poly­(ethylene adipate) (PEA), α-form crystals assemble as a RLS; at the same time, a mixture of α and β - crystals organizes into a RBS. , By contrast, PCL results in a ringless to banded morphology at higher T c (>46 °C) without the influence of the crystal structure. , Polyesters like poly­(ethylene succinate) (PESu) − result in RLS in most of the crystallization conditions, whereas high-density polyethylene (HDPE) always crystallizes with a banded morphology even at low temperatures <90 °C . Usually, polymeric RBS cannot form uniformly spaced bands across the entire range of radius, which is an inherent limitation due to growth drainage and kinetic fluctuation.…”