Comparison of Cyclic and Linear Poly(lactide)s Using Small-Angle Neutron Scattering

Philip B. Yang, Matthew G. Davidson, Karen J. Edler, Niamh Leaman, Elly K. Bathke, Strachan N. McCormick, Olga Matsarskaia, Steven Brown

Research output: Contribution to journalArticlepeer-review


Small-angle neutron scattering (SANS) experiments were conducted on cyclic and linear polymers of racemic and l-lactides (PLA) with the goal of comparing chain configurations, scaling, and effective polymer-solvent interactions of the two topologies in acetone-d6and THF-d8. There are limited reports of SANS results on cyclic polymers due to the lack of substantial development in the field until recently. Now that pure, well-defined cyclic polymers are accessible, unanswered questions about their rheology and physical conformations can be better investigated. Previously reported SANS experiments have used cyclic and linear polystyrene samples; therefore, our work allowed for direct comparison using a contrasting (structurally and sterically) polymer. We compared SANS results of cyclic and linear PLA samples with various microstructures and molecular weights at two different temperatures, allowing for comparison with a wide range of variables. The results followed the trends of previous experiments, but much greater differences in the effective polymer-solvent interaction parameters between cyclic and linear forms of PLA were observed, implying that the small form factor and hydrogen bonding in PLA allowed for much more compact conformations in the cyclic form only. Also, the polymer microstructure was found to influence polymer-solvent interaction parameters substantially. These results illustrate how the difference in polymer-solvent interactions between cyclic and linear polymers can vary greatly depending on the polymer in question and the potential of neutron scattering as a tool for identification and characterization of the cyclic topology.

Original languageEnglish
Pages (from-to)11051-11058
Number of pages8
Issue number24
Early online date13 Dec 2022
Publication statusPublished - 27 Dec 2022

Bibliographical note

Funding Information:
We would like to acknowledge the University of Bath, the Centre for Sustainable and Circular Technologies (CSCT), and Scott Bader for their support to P.B.Y. in his PhD studies. We would also like to acknowledge the CSCT, funded by the EPSRC (EP/L016354/1) for PhD support to P.B.Y., N.L., and E.K.B. We thank ILL for the award of beamtime to conduct these experiments under experiment number 9-11-2065 (doi: 10.5291/ILL-DATA.9-11-2065 ) and Professor Michael J. A. Hore (Case Western Reserve University, Cleveland, Ohio 44106, United States) for his assistance with the RPA model for fitting this data. This work benefited from the use of the SasView application, originally developed under NSF award DMR-0520547. SasView contains code developed with funding from the European Union’s Horizon 2020 research and innovation program under the SINE2020 project, grant agreement no. 654000. The data for these experiments are freely available on the University of Bath Research Data Archive ( ).

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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