From Nano-Crystals to Periodically Aggregated Assembly in Arylate Polyesters-Continuous Helicoid or Discrete...

Area of Science:

• Polymer Science
• Materials Science
• Crystallography

Background:

• Arylate polymers exhibit complex crystalline structures.
• Understanding polymer self-assembly is crucial for materials design.

Purpose of the Study:

• To investigate the universal mechanisms of self-assembly in model arylate polymers.
• To analyze the formation of periodically banded spherulites and their internal structure.

Main Methods:

• Utilized several model arylate polymers with varying methylene segment lengths (n=3, 9, 10, 12).
• Employed 3D dissection and Scanning Electron Microscopy (SEM) to probe crystal assembly.
• Analyzed poly(decamethylene terephthalate) (PDT) spherulites at a crystallization temperature (Tc) of 90 °C.

Main Results:

• All studied polymers formed similar periodically banded spherulites regardless of Tc or kinetic factors.
• 3D dissection revealed multi-shell spheroid bands composed of perpendicularly intersecting lamellae.
• Each 4 μm shell consisted of tangential and radial lamellae, with shell thickness matching optical inter-band spacing.

Conclusions:

• Established universal mechanisms for nano- to microscale crystal self-assembly in these arylate polymers.
• Demonstrated that the internal lamellar structure dictates the observed banded spherulite morphology.
• Confirmed the self-assembly process through collective analysis of multiple arylate polymer types.