Article

Dynamic urea bond for the design of reversible and self-healing polymers

  • Nature Communications 5, Article number: 3218 (2014)
  • doi:10.1038/ncomms4218
  • Download Citation
Received:
Accepted:
Published online:

Abstract

Polymers bearing dynamic covalent bonds may exhibit dynamic properties, such as self-healing, shape memory and environmental adaptation. However, most dynamic covalent chemistries developed so far require either catalyst or change of environmental conditions to facilitate bond reversion and dynamic property change in bulk materials. Here we report the rational design of hindered urea bonds (urea with bulky substituent attached to its nitrogen) and the use of them to make polyureas and poly(urethane-urea)s capable of catalyst-free dynamic property change and autonomous repairing at low temperature. Given the simplicity of the hindered urea bond chemistry (reaction of a bulky amine with an isocyanate), incorporation of the catalyst-free dynamic covalent urea bonds to conventional polyurea or urea-containing polymers that typically have stable bulk properties may further broaden the scope of applications of these widely used materials.

  • Compound C14H26N2O3

    2-(3-(tert-Butyl)-3-isopropylureido)ethyl methacrylate

  • Compound C13H24N2O3

    2-(3-(tert-Butyl)-3-ethylureido)ethyl methacrylate

  • Compound C13H24N2O3

    2-(3,3-Diisopropylureido)ethyl methacrylate

  • Compound C11H20N2O3

    2-(3,3-Diethylureido)ethyl methacrylate

  • Compound C12H22N2O3

    2-(3-(tert-Butyl)-3-methylureido)ethyl methacrylate

Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.

References

  1. 1.

    , , & Supramolecular polymers. Chem. Rev. 101, 4071–4098 (2001).

  2. 2.

    , , , & Dynamic covalent chemistry. Angew. Chem. Int. Ed. 41, 898–952 (2002).

  3. 3.

    Dynamers: dynamic molecular and supramolecular polymers. Prog. Polym. Sci. 30, 814–831 (2005).

  4. 4.

    , & Using the dynamic bond to access macroscopically responsive structurally dynamic polymers. Nat. Mater. 10, 14–27 (2011).

  5. 5.

    , , & Covalent Adaptable Networks (CANS): a unique paradigm in cross-linked polymers. Macromolecules 43, 2643–2653 (2010).

  6. 6.

    , & Light-triggered self-healing and shape-memory polymers. Chem. Soc. Rev. 42, 7244–7256 (2013).

  7. 7.

    et al. Reversible polymers formed from self-complementary monomers using quadruple hydrogen bonding. Science 278, 1601–1604 (1997).

  8. 8.

    , , & Self-healing supramolecular block copolymers. Angew. Chem. Int. Ed. 51, 10561–10565 (2012).

  9. 9.

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

  10. 10.

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

  11. 11.

    , , , & Macroscopic self-assembly through molecular recognition. Nat. Chem. 3, 34–37 (2011).

  12. 12.

    , , & Redox-responsive self-healing materials formed from host-guest polymers. Nat. Commun. 2, 551 (2011).

  13. 13.

    & Dynamers: polyacylhydrazone reversible covalent polymers, component exchange, and constitutional diversity. Proc. Natl Acad. Sci. USA 101, 8270–8275 (2004).

  14. 14.

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

  15. 15.

    , , & Photoinduced plasticity in cross-linked polymers. Science 308, 1615–1617 (2005).

  16. 16.

    , , , & Repeatable photoinduced self-healing of covalently cross-linked polymers through reshuffling of trithiocarbonate units. Angew. Chem. Int. Ed. 50, 1660–1663 (2011).

  17. 17.

    , , & Self-healing of covalently cross-linked polymers by reshuffling thiuram disulfide moieties in air under visible light. Adv. Mater. 24, 3975–3980 (2012).

  18. 18.

    & The world of smart healable materials. Prog. Polym. Sci. 35, 223–251 (2010).

  19. 19.

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

  20. 20.

    , , , & Self-healing materials with microvascular networks. Nat. Mater. 6, 581–585 (2007).

  21. 21.

    , , , & Self-healing stretchable wires for reconfigurable circuit wiring and 3D microfluidics. Adv. Mater. 25, 1589–1592 (2013).

  22. 22.

    et al. pH-induced metal-ligand cross-links inspired by mussel yield self-healing polymer networks with near-covalent elastic moduli. Proc. Natl Acad. Sci. USA 108, 2651–2655 (2011).

  23. 23.

    , , & Multiphase design of autonomic self-healing thermoplastic elastomers. Nat. Chem. 4, 467–472 (2012).

  24. 24.

    et al. Multichannel and repeatable self-healing of mechanical enhanced graphene-thermoplastic polyurethane composites. Adv. Mater. 25, 2224–2228 (2013).

  25. 25.

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

  26. 26.

    et al. Rapid self-healing hydrogels. Proc. Natl Acad. Sci. USA 109, 4383–4388 (2012).

  27. 27.

    , , & Self-healing and thermoreversible rubber from supramolecular assembly. Nature 451, 977–980 (2008).

  28. 28.

    et al. High-strength, healable, supramolecular polymer nanocomposites. J. Am. Chem. Soc. 134, 5362–5368 (2012).

  29. 29.

    & Self-repairing oxetane-substituted chitosan polyurethane networks. Science 323, 1458–1460 (2009).

  30. 30.

    et al. Self-healing of chemical gels cross-linked by diarylbibenzofuranone-based trigger-free dynamic covalent bonds at room temperature. Angew. Chem. Int. Ed. 51, 1138–1142 (2012).

  31. 31.

    , & Externally triggered healing of a thermoreversible covalent network via self-limited hysteresis heating. Adv. Mater. 22, 2784–2787 (2010).

  32. 32.

    , , , & Room temperature dynamic polymers based on Diels-Alder chemistry. Chem. Eur. J. 15, 1893–1900 (2009).

  33. 33.

    et al. Fast and catalyst-free hetero-Diels-Alder chemistry for on demand cyclable bonding/debonding materials. Polym. Chem. 4, 4348–4355 (2013).

  34. 34.

    & A surprise from 1954: siloxane equilibration is a simple, robust, and obvious polymer self-healing mechanism. J. Am. Chem. Soc. 134, 2024–2027 (2012).

  35. 35.

    & Olefin metathesis for effective polymer healing via dynamic exchange of strong carbon-carbon double bonds. J. Am. Chem. Soc. 134, 14226–14231 (2012).

  36. 36.

    , , & Making insoluble polymer networks malleable via olefin metathesis. J. Am. Chem. Soc. 134, 8424–8427 (2012).

  37. 37.

    , , & Silica-like malleable materials from permanent organic networks. Science 334, 965–968 (2011).

  38. 38.

    , , & Metal-catalyzed transesterification for healing and assembling of thermosets. J. Am. Chem. Soc. 134, 7664–7667 (2012).

  39. 39.

    , , , & High isolated yields in thermodynamically controlled peptide synthesis in toluene catalysed by thermolysin adsorbed on celite R-640. Chem. Commun. 467–468 (2000).

  40. 40.

    et al. Switching pathways: room-temperature neutral solvolysis and substitution of amides. Angew. Chem. Int. Ed. 51, 548–551 (2012).

  41. 41.

    & Urea dissociation. a measure of steric hindrance in secondary amines. J. Org. Chem. 39, 2448–2449 (1974).

  42. 42.

    et al. Hindered ureas as masked isocyanates: facile carbamoylation of nucleophiles under neutral conditions. Angew. Chem. Int. Ed. 48, 8721–8724 (2009).

  43. 43.

    & Nucleation-elongation: a mechanism for cooperative supramolecular polymerization. Org. Biomol. Chem. 1, 3471–3491 (2003).

Download references

Acknowledgements

We acknowledge the supports from the United States National Science Foundation (CHE 1153122) and the United States National Institute of Health (Director’s New Innovator Award 1DP2OD007246-01). We thank Professor Nancy Sottos for letting us use her laboratory equipment for the mechanical analysis of the polymer materials, and Brett Beiermann in the Sottos group for training H.Y. to use the instrument and analyse the mechanical properties of the materials. We also thank Catherine Yao for helping on preparing schematic illustrations.

Author information

Affiliations

  1. Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, 1304 West Green Street, Urbana, Illinois 61801, USA

    • Hanze Ying
    • , Yanfeng Zhang
    •  & Jianjun Cheng

Authors

  1. Search for Hanze Ying in:

  2. Search for Yanfeng Zhang in:

  3. Search for Jianjun Cheng in:

Contributions

H.Y. and J.C. planned the project and designed experiments. Y.Z. contributed to the project design. H.Y. carried out the experiments and collected data. H.Y. and J.C. analysed the experimental data, prepared figures and wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Jianjun Cheng.

Supplementary information

PDF files

  1. 1.

    Supplementary Figures, Table and Notes.

    Supplementary Figures 1-9, Supplementary Table 1 and Supplementary Notes 1-3

Videos

  1. 1.

    Supplementary Movie 1

    Stress-strain analysis of 6c cut and then healed for 48 h at 37 °C.

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.