Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Fundamental limits of material toughening in molecularly confined polymers

Nature Materials volume 15, pages 294–298 (2016)Cite this article

Subjects

Abstract

The exceptional mechanical properties of polymer nanocomposites are achieved through intimate mixing of the polymer and inorganic phases, which leads to spatial confinement of the polymer phase1,2,3,4,5. In this study we probe the mechanical and fracture properties of polymers in the extreme limits of molecular confinement, where a stiff inorganic phase confines the polymer chains to dimensions far smaller than their bulk radius of gyration. We show that polymers confined at molecular length scales dissipate energy through a confinement-induced molecular bridging mechanism that is distinct from existing entanglement-based theories of polymer deformation and fracture. We demonstrate that the toughening is controlled by the molecular size and the degree of confinement, but is ultimately limited by the strength of individual molecules.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Hybrid nanocomposite filling process and characterization.
Figure 2: The local environment of polymer chains in the matrix changes considerably with molecular mass.
Figure 3: Cohesive fracture energy of hybrid nanocomposites with varying polymer molecular masses.
Figure 4: Calculations of tensile strength, bridging displacement and bridging force for polystyrene chains.

Similar content being viewed by others

References

  1. Paul, D. R. & Robeson, L. M. Polymer nanotechnology: Nanocomposites. Polymer 49, 3187–3204 (2008).

    Article  CAS  Google Scholar 

  2. Sanchez, C., Julián, B., Belleville, P. & Popall, M. Applications of hybrid organic–inorganic nanocomposites. J. Mater. Chem. 15, 3559–3592 (2005).

    Article  CAS  Google Scholar 

  3. Alexandre, M. & Dubois, P. Polymer layered-silicate nanocomposites: Preparation, properties and uses of a new class of materials. Mater. Sci. Eng. R 28, 1–63 (2000).

    Article  Google Scholar 

  4. Coleman, J. N., Khan, U., Blau, W. J. & Gun’ko, Y. K. Small but strong: A review of the mechanical properties of carbon nanotube-polymer composites. Carbon 44, 1624–1652 (2006).

    Article  CAS  Google Scholar 

  5. Gao, H., Ji, B., Jager, I. L., Arzt, E. & Fratzl, P. Materials become insensitive to flaws at nanoscale: Lessons from nature. Proc. Natl Acad. Sci. USA 100, 5597–5600 (2003).

    Article  CAS  Google Scholar 

  6. Giesa, T., Arslan, M., Pugno, N. M. & Buehler, M. J. Nanoconfinement of spider silk fibrils begets superior strength, extensibility, and toughness. Nano Lett. 11, 5038–5046 (2011).

    Article  CAS  Google Scholar 

  7. Keten, S., Xu, Z., Ihle, B. & Buehler, M. J. Nanoconfinement controls stiffness, strength and mechanical toughness of β-sheet crystals in silk. Nature Mater. 9, 359–367 (2010).

    Article  CAS  Google Scholar 

  8. Czanderna, A. W. & Pern, F. J. Encapsulation of PV modules using ethylene vinyl acetate copolymer as a pottant: A critical review. Sol. Energy Mater. Sol. Cells 43, 101–181 (1996).

    Article  CAS  Google Scholar 

  9. Niu, M. C. Y. Composite Airframe Structures 3rd edn (Adaso/Adastra Eng., 1992).

    Google Scholar 

  10. Mackay, M. E. et al. General strategies for nanoparticle dispersion. Science 311, 1740–1743 (2006).

    Article  CAS  Google Scholar 

  11. Krishnamoorti, R., Vaia, R. A. & Giannelis, E. P. Structure and dynamics of polymer-layered silicate nanocomposites. Chem. Mater. 8, 1728–1734 (2013).

    Article  Google Scholar 

  12. Fatkullin, N. et al. The confined-to-bulk dynamics transition of polymer melts in nanoscopic pores of solid matrices with varying pore diameter. New J. Phys. 6, 46–46 (2004).

    Article  Google Scholar 

  13. Schönhals, A., Goering, H., Schick, C., Frick, B. & Zorn, R. Glassy dynamics of polymers confined to nanoporous glasses revealed by relaxational and scattering experiments. Eur. Phys. J. E 12, 173–178 (2003).

    Article  Google Scholar 

  14. Shin, K. et al. Enhanced mobility of confined polymers. Nature Mater. 6, 961–965 (2007).

    Article  CAS  Google Scholar 

  15. De Gennes, P.-G. Scaling Concepts in Polymer Physics (Cornell Univ. Press, 1979).

    Google Scholar 

  16. Si, L., Massa, M. V., Dalnoki-Veress, K., Brown, H. R. & Jones, R. A. L. Chain entanglement in thin freestanding polymer films. Phys. Rev. Lett. 94, 127801 (2005).

    Article  Google Scholar 

  17. Mikos, A. G. & Peppas, N. A. Polymer chain entanglements and brittle fracture. J. Chem. Phys. 88, 1337–1342 (1988).

    Article  CAS  Google Scholar 

  18. Adolf, D., Tirrell, M. & Prager, S. Molecular weight dependence of healing and brittle fracture in amorphous polymers above the entanglement molecular weight. J. Polym. Sci. B 23, 413–427 (1985).

    CAS  Google Scholar 

  19. Frot, T. et al. Post porosity plasma protection: Scaling of efficiency with porosity. Adv. Funct. Mater. 22, 3043–3050 (2012).

    Article  CAS  Google Scholar 

  20. Guyer, E. P., Patz, M. & Dauskardt, R. H. Fracture of nanoporous methyl silsesquioxane thin-film glasses. J. Mater. Res. 21, 882–894 (2011).

    Article  Google Scholar 

  21. Kinloch, A. J. & Young, R. J. Fracture Behaviour of Polymers (Applied Science Publishers, 1983).

    Google Scholar 

  22. Pitman, G. L. & Ward, I. M. Effect of molecular weight on craze shape and fracture toughness in polycarbonate. Polymer 20, 895–902 (1979).

    Article  CAS  Google Scholar 

  23. Bao, G. & Suo, Z. Remarks on crack-bridging concepts. Appl. Mech. Rev. 45, 355–366 (1992).

    Article  Google Scholar 

  24. Kramer, E. Microscopic and molecular fundamentals of crazing. Adv. Polym. Sci. 52–53, 1–56 (1983).

    Google Scholar 

  25. Odell, J. A. & Keller, A. Flow-induced chain fracture of isolated linear macromolecules in solution. J. Polym. Sci. B 24, 1889–1916 (1986).

    Article  CAS  Google Scholar 

  26. Beyer, M. K. & Clausen-Schaumann, H. Mechanochemistry: The mechanical activation of covalent bonds. Chem. Rev. 105, 2921–2948 (2005).

    Article  CAS  Google Scholar 

  27. Sambasivam, M., Klein, A. & Sperling, L. H. Energy-consuming micromechanisms in the fracture of glassy polymers. 2. Effect of molecular weight on the fracture of polystyrene. Macromolecules 28, 152–159 (1995).

    Article  CAS  Google Scholar 

  28. Sutcu, M. Weibull statistics applied to fiber failure in ceramic composites and work of fracture. Acta Metall. 37, 651–661 (1989).

    Article  CAS  Google Scholar 

  29. Sussman, D. M., Tung, W.-S., Winey, K. I., Schweizer, K. S. & Riggleman, R. A. Entanglement reduction and anisotropic chain and primitive path conformations in polymer melts under thin film and cylindrical confinement. Macromolecules 47, 6462–6472 (2014).

    Article  CAS  Google Scholar 

  30. Frot, T., Volksen, W., Purushothaman, S., Bruce, R. & Dubois, G. Application of the protection/deprotection strategy to the science of porous materials. Adv. Mater. 23, 2828–2832 (2011).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Air Force Office of Science Research Grant No. FA9550-12-1-0120 in the Low Density Materials Program. Characterization was performed in part at the Stanford Nano Shared Facilities (SNSF).

Author information

Authors and Affiliations

  1. Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305, USA

    Scott G. Isaacson, Yusuke Matsuda, Reinhold H. Dauskardt & Geraud Dubois

  2. Hybrid Polymeric Materials, IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, USA

    Krystelle Lionti, Willi Volksen, Teddie P. Magbitang & Geraud Dubois

Authors
  1. Scott G. Isaacson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Krystelle Lionti
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Willi Volksen
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Teddie P. Magbitang
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Yusuke Matsuda
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Reinhold H. Dauskardt
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Geraud Dubois
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

S.G.I. and Y.M. made DCB specimens and collected and analysed fracture data. S.G.I. performed simulations. K.L. fabricated and characterized the hybrid nanocomposites. W.V. synthesized the nanoporous matrix. T.P.M. performed GPC analyses. S.G.I. and R.H.D. constructed the molecular bridging model. S.G.I., G.D. and R.H.D. wrote the paper and designed the study.

Corresponding authors

Correspondence to Reinhold H. Dauskardt or Geraud Dubois.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 779 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Isaacson, S., Lionti, K., Volksen, W. et al. Fundamental limits of material toughening in molecularly confined polymers. Nature Mater 15, 294–298 (2016). https://doi.org/10.1038/nmat4475

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat4475

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing