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Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS₂NT Nanocomposite Tubes

Rocher, Lison and Ylitalo, Andrew S. and Di Luccio, Tiziana and Miscioscia, Riccardo and De Filippo, Giovanni and Pandolfi, Giuseppe and Villani, Fulvia and Zak, Alla and Menary, Gary H. and Lennon, Alex B. and Kornfield, Julia A. (2021) Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS₂NT Nanocomposite Tubes. Polymers, 13 (11). Art. No. 1764. ISSN 2073-4360. PMCID PMC8198810. doi:10.3390/polym13111764.

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In situ synchrotron X-ray scattering was used to reveal the transient microstructure of poly(L-lactide) (PLLA)/tungsten disulfide inorganic nanotubes (WS₂NTs) nanocomposites. This microstructure is formed during the blow molding process (“tube expansion”) of an extruded polymer tube, an important step in the manufacturing of PLLA-based bioresorbable vascular scaffolds (BVS). A fundamental understanding of how such a microstructure develops during processing is relevant to two unmet needs in PLLA-based BVS: increasing strength to enable thinner devices and improving radiopacity to enable imaging during implantation. Here, we focus on how the flow generated during tube expansion affects the orientation of the WS₂NTs and the formation of polymer crystals by comparing neat PLLA and nanocomposite tubes under different expansion conditions. Surprisingly, the WS₂NTs remain oriented along the extrusion direction despite significant strain in the transverse direction while the PLLA crystals (c-axis) form along the circumferential direction of the tube. Although WS₂NTs promote the nucleation of PLLA crystals in nanocomposite tubes, crystallization proceeds with largely the same orientation as in neat PLLA tubes. We suggest that the reason for the unusual independence of the orientations of the nanotubes and polymer crystals stems from the favorable interaction between PLLA and WS₂NTs. This favorable interaction leads WS₂NTs to disperse well in PLLA and strongly orient along the axis of the PLLA tube during extrusion. As a consequence, the nanotubes are aligned orthogonally to the circumferential stretching direction, which appears to decouple the orientations of PLLA crystals and WS₂NTs.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Ylitalo, Andrew S.0000-0003-4086-3508
Miscioscia, Riccardo0000-0001-6586-4182
Menary, Gary H.0000-0003-2771-7258
Lennon, Alex B.0000-0003-2722-8227
Kornfield, Julia A.0000-0001-6746-8634
Alternate Title:Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS2NT Nanocomposite Tubes
Additional Information:© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Received: 21 April 2021; Revised: 19 May 2021; Accepted: 24 May 2021; Published: 27 May 2021. L.R. would like to thank Graham Garrett for his help and advice during tube extrusion, Boston Scientific Ltd. (Marlborough, MA, USA) for their support and collaboration, and Corbion Biomaterials, The Netherlands, for the kind gift of PLLA. The authors acknowledge Karthik Ramachandran for providing the initial Matlab code to analyze the scattering data, Orland Bateman, Karl Joyce, Brian Dillon, and John Dale for their help and expertise with the microcopy analysis, and also Jordan Barr and Judith Cameron for performing the offline experiments in water bath. The authors would also like to thank all the staff at beamline 5-ID-D DND-CAT of the Advanced Photon Source (APS) at the Argonne National Laboratories, especially Steven Weigand, for their invaluable support for the success of the experiments. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreements No 813869 and No 691238. This publication article reflects only the author’s view, and the REA is not responsible for any use that may be made of the information it contains. A.Y. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. A. Z. acknowledges Israel Science Foundation (ISF 330-16) for supporting synthesis of WS₂ nanotubes. Author Contributions: A.Z. synthesized the WS₂ nanotubes and analyzed them by SEM and TEM; G.H.M., A.B.L., T.D.L. and J.A.K. designed research; L.R. manufactured the preforms; R.M., G.D.F., and G.P. constructed the apparatus; L.R., A.S.Y., F.V., R.M., G.D.F., G.P. and T.D.L. performed experiments; L.R., A.S.Y., T.D.L. and J.A.K. analyzed data; L.R., R.M., A.S.Y., A.Z., G.H.M., A.B.L., T.D.L. and J.A.K. wrote the paper. All authors have read and agreed to the published version of the manuscript. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. The authors declare no conflict of interest.
Funding AgencyGrant Number
Marie Curie Fellowship813869
Marie Curie Fellowship691238
NSF Graduate Research FellowshipDGE-1745301
Israel Science Foundation330-16
Subject Keywords:polylactide; tungsten disulfide nanotubes; nanocomposites; blow molding; WAXS; SAXS; bioresorbable vascular scaffold
Issue or Number:11
PubMed Central ID:PMC8198810
Record Number:CaltechAUTHORS:20210603-162823845
Persistent URL:
Official Citation:Rocher, L.; Ylitalo, A.S.; Luccio, T.D.; Miscioscia, R.; De Filippo, G.; Pandolfi, G.; Villani, F.; Zak, A.; Menary, G.H.; Lennon, A.B.; et al. Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS2NT Nanocomposite Tubes. Polymers 2021, 13, 1764.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109375
Deposited By: Tony Diaz
Deposited On:04 Jun 2021 17:09
Last Modified:21 Jun 2021 18:11

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