Simulation of SAXS patterns from oriented lamellar structures and their elliptical trajectories

David T. Grubb, W. Joshua Kennedy, Hilmar Koerner, N. Sanjeeva Murthy

Research output: Contribution to journalArticlepeer-review


Small-angle X-ray Scattering (SAXS) patterns are useful for studying the organization of crystalline and amorphous regions that make up a semi-crystalline polymer and influence its properties. To understand how these patterns originate and evolve during deformation, three distinct SAXS patterns (2-point, 4-point ‘eyebrow’, and 4-point ‘butterfly’) were generated using simple microstructural models and compared in detail with experimental data from poly(ethylene-co-octene). As the patterns typically contain a single unique reflection, it is not possible to fully determine the structure from the patterns alone. Therefore, structural models with lamellar stacks were used to simulate SAXS patterns. When stack orientation (interlamellar shear) and chain slip act to rotate lamellae in the same sense, the result is an ‘eyebrow’ pattern. Opposite senses give a ‘butterfly’ pattern. Experimental patterns often have reflections where the peak position traces out an ellipse. Adding moderate amounts of rotational disorder to the models produces this effect without any elliptical correlations or deformed lattice in the material.

Original languageAmerican English
Article number123566
StatePublished - Apr 2 2021

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


  • Butterfly pattern
  • Diffraction pattern simulation
  • Small-angle scattering. lamellar structures. polymer crystal lamellae. eyebrow pattern


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