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.

  • Article
  • Published:

A highly stretchable autonomous self-healing elastomer

Abstract

It is a challenge to synthesize materials that possess the properties of biological muscles—strong, elastic and capable of self-healing. Herein we report a network of poly(dimethylsiloxane) polymer chains crosslinked by coordination complexes that combines high stretchability, high dielectric strength, autonomous self-healing and mechanical actuation. The healing process can take place at a temperature as low as −20 °C and is not significantly affected by surface ageing and moisture. The crosslinking complexes used consist of 2,6-pyridinedicarboxamide ligands that coordinate to Fe(III) centres through three different interactions: a strong pyridyl–iron one, and two weaker carboxamido–iron ones through both the nitrogen and oxygen atoms of the carboxamide groups. As a result, the iron–ligand bonds can readily break and re-form while the iron centres still remain attached to the ligands through the stronger interaction with the pyridyl ring, which enables reversible unfolding and refolding of the chains. We hypothesize that this behaviour supports the high stretchability and self-healing capability of the material.

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

Access options

Buy this article

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

Figure 1: Schematic structure of material design and single-molecule force spectroscopy characterization.
Figure 2: Mechanical properties of Fe-Hpdca-PDMS.
Figure 3: Self-healing properties of the Fe-Hpdca-PDMS film (with an Fe(III) metal to H2pdca-PDMS ligand molar ratio of 1:2.
Figure 4: Self-healing artificial muscle fabricated from a Fe-Hpdca-PDMS film with an Fe(III) metal to H2pdca-PDMS ligand molar ratio of 1:2.

Similar content being viewed by others

References

  1. Wu, D. Y., Meure, S. & Solomon, D. Self-healing polymeric materials: a review of recent developments. Prog. Polym. Sci. 33, 479–522 (2008).

    CAS  Google Scholar 

  2. Yang, Y. & Urban, M. W. Self-healing polymeric materials. Chem. Soc. Rev. 42, 7446–7467 (2013).

    CAS  PubMed  Google Scholar 

  3. Binder, W. H. Self-Healing Polymers: From Principles to Applications (Wiley-VCH, 2013).

    Google Scholar 

  4. Burnworth, M. et al. Optically healable supramolecular polymers. Nature 472, 334–337 (2011).

    CAS  PubMed  Google Scholar 

  5. Ghosh, B. & Urban, M. W. Self-repairing oxetane-substituted chitosan polyurethane networks. Science 323, 1458–1460 (2009).

    CAS  PubMed  Google Scholar 

  6. Chen, X. et al. A thermally re-mendable cross-linked polymeric material. Science 295, 1698–1702 (2002).

    CAS  PubMed  Google Scholar 

  7. Toohey, K. S., Sottos, N. R., Lewis, J. A., Moore, J. S. & White, S. R. Self-healing materials with microvascular networks. Nature Mater. 6, 581–585 (2007).

    CAS  Google Scholar 

  8. Caruso, M. M. et al. Solvent-promoted self-healing epoxy materials. Macromolecules 40, 8830–8832 (2007).

    CAS  Google Scholar 

  9. Jackson, A. C., Bartelt, J. A. & Braun, P. V. Transparent self-healing polymers based on encapsulated plasticizers in a thermoplastic matrix. Adv. Funct. Mater. 21, 4705–4711 (2011).

    CAS  Google Scholar 

  10. White, S. R. et al. Autonomic healing of polymer composites. Nature 409, 794–797 (2001).

    CAS  PubMed  Google Scholar 

  11. Wang, Q. et al. High-water-content mouldable hydrogels by mixing clay and a dendritic molecular binder. Nature 463, 339–343 (2010).

    CAS  PubMed  Google Scholar 

  12. Cordier, P., Tournilhac, F., Soulie-Ziakovic, C. & Leibler, L. Self-healing and thermoreversible rubber from supramolecular assembly. Nature 451, 977–980 (2008).

    CAS  PubMed  Google Scholar 

  13. Tee, B. C.-K., Wang, C., Allen, R. & Bao, Z. An electrically and mechanically self-healing composite with pressure- and flexion-sensitive properties for electronic skin applications. Nature Nanotech. 7, 825–832 (2012).

    CAS  Google Scholar 

  14. Chen, Y., Kushner, A. M., Williams, G. A. & Guan, Z. Multiphase design of autonomic self-healing thermoplastic elastomers. Nature Chem. 4, 467–472 (2012).

    CAS  Google Scholar 

  15. Wang, C. et al. A rapid and efficient self-healing thermo-reversible elastomer crosslinked with graphene oxide. Adv. Mater. 25, 5785–5790 (2013).

    CAS  PubMed  Google Scholar 

  16. Balkenende, D. W. R. et al. Mechanochemistry with metallosupramolecular polymers. J. Am. Chem. Soc. 136, 10493–10498 (2014).

    CAS  PubMed  Google Scholar 

  17. Bode, S. et al. Self-healing polymer coatings based on crosslinked metallosupramolecular copolymers. Adv. Mater. 25, 1634–1638 (2013).

    CAS  PubMed  Google Scholar 

  18. Bode, S. et al. Self-healing metallopolymers based on cadmium bis(terpyridine) complex containing polymer networks. Polym. Chem. 4, 4966–4973 (2013).

    CAS  Google Scholar 

  19. Sandmann, B. et al. The self-healing potential of triazole–pyridine-based metallopolymers. Macromol. Rapid Commun. 36, 604–609 (2015).

    CAS  PubMed  Google Scholar 

  20. Yang, B. et al. Self-healing metallo-supramolecular polymers from a ligand macromolecule synthesized via copper-catalyzed azide–alkyne cycloaddition and thiol–ene double ‘click’ reactions. Polym. Chem. 5, 1945–1953 (2014).

    CAS  Google Scholar 

  21. Krogsgaard, M., Behrens, M. A., Pedersen, J. S. & Birkedal, H. Self-healing mussel-inspired multi-pH-responsive hydrogels. Biomacromolecules 14, 297–301 (2013).

    CAS  PubMed  Google Scholar 

  22. Basak, S., Nanda, J. & Banerjee, A. Multi-stimuli responsive self-healing metallo-hydrogels: tuning of the gel recovery property. Chem. Commun. 50, 2356–2359 (2014).

    CAS  Google Scholar 

  23. Zheng, P., Wang, Y. & Li, H. Reversible unfolding–refolding of rubredoxin: a single-molecule force spectroscopy study. Angew. Chem. Int. Ed. 53, 14060–14063 (2014).

    CAS  Google Scholar 

  24. Zheng, P., Arantes, G. M., Field, M. J. & Li, H. Force-induced chemical reactions on the metal centre in a single metalloprotein molecule. Nature Commun. 6, 7569 (2015).

    CAS  Google Scholar 

  25. Sollich, P. Rheological constitutive equation for a model of soft glassy materials. Phys. Rev. E 58, 738–759 (1998).

    CAS  Google Scholar 

  26. Sun, J. Y. et al. Highly stretchable and tough hydrogels. Nature 489, 133–136 (2012).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. Sun, T. L. et al. Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity. Nature Mater. 12, 932–937 (2013).

    CAS  Google Scholar 

  28. Bhowmick, A. K., & Stephens, H. Handbook of Elastomers (CRC Press, 2000).

    Google Scholar 

  29. Iyer, B. V. S. et al. Modeling the response of dual cross-linked nanoparticle networks to mechanical deformation. Soft Matter 9, 109–121 (2013).

    CAS  Google Scholar 

  30. Iyer, B. V. S. et al. Strain recovery and self-healing in dual cross-linked nanoparticle networks. Polymer Chem. 4, 4927–4939 (2013).

    CAS  Google Scholar 

  31. Iyer, B. V. et al. Ductility, toughness and strain recovery in self-healing dual cross-linked nanoparticle networks studied by computer simulations. Prog. Polymer Sci. 40, 121–137 (2015).

    CAS  Google Scholar 

  32. Gossweiler, G. R. et al. Mechanochemical activation of covalent bonds in polymers with full and repeatable macroscopic shape recovery. ACS Macro Lett. 3, 216–219 (2014).

    CAS  Google Scholar 

  33. Holten-Anderson, N. et al. pH-induced metal–ligand crosslinks inspired by mussel yield self-healing polymer networks with near covalent elastic moduli. Proc. Natl Acad. Sci. USA 108, 2651 (2011).

    Google Scholar 

  34. Grindy, S. C. et al. Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics. Nature Mater. 14, 1210–1216 (2015).

    CAS  Google Scholar 

  35. Kushner, A. M., Gabuchian, V., Johnson, E. G. & Guan, Z. Biomimetic design of reversibly unfolding cross-linker to enhance mechanical properties of 3D network polymers. J. Am. Chem. Soc. 129, 14110–14111 (2007).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Burattini, S. et al. A healable supramolecular polymer blend based on aromatic ππ stacking and hydrogen-bonding interactions. J. Am. Chem. Soc. 132, 12051–12058 (2010).

    CAS  PubMed  Google Scholar 

  37. Kakuta, T. et al. Preorganized hydrogel: self-healing properties of supramolecular hydrogels formed by polymerization of host–guest-monomers that contain cyclodextrins and hydrophobic guest groups. Adv. Mater. 25, 2849–2853 (2013).

    CAS  PubMed  Google Scholar 

  38. Mozhdehi, D., Ayala, S., Cromwell, O. R. & Guan, Z. Self-healing multiphase polymers via dynamic metal–ligand interactions. J. Am. Chem. Soc. 136, 16128–16131 (2014).

    CAS  PubMed  Google Scholar 

  39. Pelrine, R., Kornbluh, R., Pei, Q. & Joseph, J. High-speed electrically actuated elastomers with strain greater than 100%. Science 287, 836–839 (2000).

    CAS  PubMed  Google Scholar 

  40. Anderson, I. A., Gisby, T. A., McKay, T. G., O'Brien, B. M. & Calius, E. P. Multi-functional dielectric elastomer artificial muscles for soft and smart machines. J. Appl. Phys. 112, 041101 (2012).

    Google Scholar 

  41. Keplinger, C. et al. Stretchable, transparent, ionic conductors. Science 341, 984–987 (2013).

    CAS  PubMed  Google Scholar 

  42. Xie, T. Tunable polymer multi-shape memory effect. Nature 464, 267–270 (2010).

    CAS  PubMed  Google Scholar 

  43. Keplinger, C., Li, T., Baumgartner, R., Suo, Z. & Bauer, S. Harnessing snap-through instability in soft dielectrics to achieve giant voltage-triggered deformation. Soft Matter 8, 285–288 (2012).

    CAS  Google Scholar 

  44. Hunt, S., McKay, T. G. & Anderson, I. A. A self-healing dielectric elastomer actuator. Appl. Phys. Lett. 104, 113701 (2014).

    Google Scholar 

  45. Yuan, W. et al. Fault-tolerant dielectric elastomer actuators using single-walled carbon nanotube electrodes. Adv. Mater. 20, 621–625 (2008).

    CAS  Google Scholar 

Download references

Acknowledgements

This work was partially supported by the Major State Basic Research Development Program (Grant No. 2013CB922100 and Grant No. 2011CB808704), Air Force Office of Scientific Research (FA9550-15-1-0106) and Samsung Electronics. F.L. thanks the Swiss National Science Foundation for an Early Mobility Postdoc grant. We thank J. Ma for helpful discussions on the DFT calculations and X. R. Lu, J. C. Lai, X. Y. Jia and J. F. Mei for assistance in the synthesis and characterization of the model complex.

Author information

Authors and Affiliations

Authors

Contributions

C.-H.L., C.W. and Z.B. conceived, designed and directed the project; C.-H.L., C.W., C.K., Y.S., P.Z., Y.C. and F.L. performed the experiments; C.-H.L., C.W., C.K., Y.S., P.Z., Y.C., F.L., J.-L.Z, X.-Z.Y., L.J., C.L. and Z.B. analysed the data; C.-H.L., C.W. and Z.B. wrote the paper. All the authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Zhenan Bao.

Ethics declarations

Competing interests

Stanford University has filed a provisional application for a patent based on this technology that names C.H.L., C.W. and Z.B. as inventors.

Supplementary information

Supplementary information

Supplementary information (PDF 1858 kb)

Supplementary information

Supplementary Movie 1 (WMV 3255 kb)

Supplementary information

Supplementary Movie 2 (WMV 2332 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Li, CH., Wang, C., Keplinger, C. et al. A highly stretchable autonomous self-healing elastomer. Nature Chem 8, 618–624 (2016). https://doi.org/10.1038/nchem.2492

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nchem.2492

This article is cited by

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