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Bio-inspired mechanically adaptive materials through vibration-induced crosslinking

Nature Materials volume 20, pages 869–874 (2021)Cite this article

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Abstract

In nature, bone adapts to mechanical forces it experiences, strengthening itself to match the conditions placed upon it. Here we report a composite material that adapts to the mechanical environment it experiences—varying its modulus as a function of force, time and the frequency of mechanical agitation. Adaptation in the material is managed by mechanically responsive ZnO, which controls a crosslinking reaction between a thiol and an alkene within a polymer composite gel, resulting in a mechanically driven ×66 increase in modulus. As the amount of chemical energy is a function of the mechanical energy input, the material senses and adapts its modulus along the distribution of stress, resembling the bone remodelling behaviour that materials can adapt accordingly to the loading location. Such material design might find use in a wide range of applications, from adhesives to materials that interface with biological systems.

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Fig. 1: Conceptual illustration of bone remodelling and synthetic self-adaptive material via mechano-thiol–ene polymerization.
Fig. 2: Strengthening of an organo-gel via mechano-chemical crosslinking.
Fig. 3: Adaptation of the organo-gel modulus to different mechanical inputs.
Fig. 4: Remodelling of material structure and modelling of force distribution.

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Source data are provided with this paper. The other data that support the findings of this study are available within the paper and its Supplementary Information files and available from the corresponding author upon reasonable request.

References

  1. Gin, S., Dillmann, P. & Birbilis, N. Material degradation foreseen in the very long term: the case of glasses and ferrous metals. NPJ Mater. Degrad. 1, 10 (2017).

    Article  Google Scholar 

  2. Patrick, J. F., Robb, M. J., Sottos, N. R., Moore, J. S. & White, S. R. Polymers with autonomous life-cycle control. Nature 540, 363–370 (2016).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  4. Diesendruck, C. E., Sottos, N. R., Moore, J. S. & White, S. R. Biomimetic self-healing. Angew. Chem. Int. Ed. 54, 10428–10447 (2015).

    Article  CAS  Google Scholar 

  5. Shchukin, D. & Möhwald, H. A coat of many functions. Science 341, 1458–1459 (2013).

    Article  CAS  Google Scholar 

  6. Chen, J.-H., Liu, C., You, L. & Simmons, C. A. Boning up on Wolff’s law: mechanical regulation of the cells that make and maintain bone. J. Biomech. 43, 108–118 (2010).

    Article  Google Scholar 

  7. Christen, P. et al. Bone remodelling in humans is load-driven but not lazy. Nat. Commun. 5, 4855 (2014).

    Article  CAS  Google Scholar 

  8. Lin, S. et al. Anti-fatigue-fracture hydrogels. Sci. Adv. 5, eaau8528 (2019).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  10. Orrego, S. et al. Bioinspired materials with self-adaptable mechanical properties. Adv. Mater. https://doi.org/10.1002/adma.201906970 (2020).

  11. Brown, E. et al. Generality of shear thickening in dense suspensions. Nat. Mater. 9, 220–224 (2010).

    Article  CAS  Google Scholar 

  12. Xu, D., Hawk, J. L., Loveless, D. M., Jeon, S. L. & Craig, S. L. Mechanism of shear thickening in reversibly cross-linked supramolecular polymer networks. Macromolecules 43, 3556–3565 (2010).

    Article  CAS  Google Scholar 

  13. Ramirez, A. L. B. et al. Mechanochemical strengthening of a synthetic polymer in response to typically destructive shear forces. Nat. Chem. https://doi.org/10.1038/nchem.1720 (2013).

  14. Li, J., Nagamani, C. & Moore, J. S. Polymer mechanochemistry: from destructive to productive. Acc. Chem. Res. 48, 2181–2190 (2015).

    Article  CAS  Google Scholar 

  15. Chen, Z. et al. Mechanochemical unzipping of insulating polyladderene to semiconducting polyacetylene. Science 357, 475–479 (2017).

    Article  CAS  Google Scholar 

  16. Baytekin, H. T., Baytekin, B. & Grzybowski, B. A. Mechanoradicals created in “polymeric sponges” drive reactions in aqueous media. Angew. Chem. Int. Ed. 51, 3596–3600 (2012).

    Article  CAS  Google Scholar 

  17. Matsuda, T., Kawakami, R., Namba, R., Nakajima, T. & Gong, J. P. Mechanoresponsive self-growing hydrogels inspired by muscle training. Science 363, 504–508 (2019).

    Article  CAS  Google Scholar 

  18. Wang, Z. et al. Ultrasonication-induced aqueous atom transfer radical polymerization. ACS Macro Lett. 7, 275–280 (2018).

    Article  CAS  Google Scholar 

  19. Collins, J. et al. Sonochemically initiated RAFT polymerization in organic solvents. Macromolecules 52, 185–195 (2019).

    Article  CAS  Google Scholar 

  20. Mohapatra, H. et al. Ultrasound promoted step-growth polymerization and polymer crosslinking via copper catalyzed azide–alkyne “click” reaction. Angew. Chem. Int. Ed. 57, 11208–11212 (2018).

    Article  CAS  Google Scholar 

  21. Ren, W., Peng, B., Shen, J., Li, Y. & Yu, Y. Study on vibration characteristics and human riding comfort of a special equipment cab. J. Sens. 2018, 7140610 (2018).

    Google Scholar 

  22. Yu, Y., Naganathan, N. G. & Dukkipati, R. V. A literature review of automotive vehicle engine mounting systems. Mech. Mach. Theory 36, 123–142 (2001).

    Article  Google Scholar 

  23. Xu, H., Yuan, S. & Zong, L. Analysis of the time-frequency characteristics of internal combustion engine vibration signal based on Hilbert-Huang transform. In 2010 3rd International Congress on Image and Signal Processing 3400–3404 (IEEE, 2010).

  24. Le, M. Q. et al. Review on energy harvesting for structural health monitoring in aeronautical applications. Prog. Aerosp. Sci. 79, 147–157 (2015).

    Article  Google Scholar 

  25. Kubota, K., Pang, Y., Miura, A. & Ito, H. Redox reactions of small organic molecules using ball milling and piezoelectric materials. Science 366, 1500–1504 (2019).

    Article  CAS  Google Scholar 

  26. Lalanne, C. Mechanical Vibration and Shock Analysis, Fatigue Damage (John Wiley & Sons, 2010).

  27. Wang, Z., Ayarza, J. & Esser-Kahn, A. P. Mechanically initiated bulk-scale free-radical polymerization. Angew. Chem. Int. Ed. 58, 12023–12026 (2019).

    Article  CAS  Google Scholar 

  28. Wang, Z. et al. Enhancing mechanically induced ATRP by promoting interfacial electron transfer from piezoelectric nanoparticles to Cu catalysts. Macromolecules 50, 7940–7948 (2017).

    Article  CAS  Google Scholar 

  29. Skinner, E. K., Whiffin, F. M. & Price, G. J. Room temperature sonochemical initiation of thiol-ene reactions. Chem. Commun. 48, 6800–6802 (2012).

    Article  CAS  Google Scholar 

  30. Lowe, A. B. Thiol–ene “click” reactions and recent applications in polymer and materials synthesis: a first update. Polym. Chem. 5, 4820–4870 (2014).

    Article  CAS  Google Scholar 

  31. Xu, J. & Boyer, C. Visible light photocatalytic thiol–ene reaction: an elegant approach for fast polymer postfunctionalization and step-growth polymerization. Macromolecules 48, 520–529 (2015).

    Article  CAS  Google Scholar 

  32. Mohapatra, H., Kleiman, M. & Esser-Kahn, A. P. Mechanically controlled radical polymerization initiated by ultrasound. Nat. Chem. 9, 135–139 (2017).

    Article  CAS  Google Scholar 

  33. Hoyle, C. E., Lee, T. Y. & Roper, T. Thiol–enes: chemistry of the past with promise for the future. J. Polym. Sci. A Polym. Chem. 42, 5301–5338 (2004).

    Article  CAS  Google Scholar 

  34. Cole, M. A., Jankousky, K. C. & Bowman, C. N. Redox initiation of bulk thiol–ene polymerizations. Polym. Chem. 4, 1167–1175 (2013).

    Article  CAS  Google Scholar 

  35. Mohinuddin, P. M. K. & Gangi Reddy, N. C. Zinc oxide catalyzed solvent-free mechanochemical route for C–S bond construction: a sustainable process. Eur. J. Org. Chem. 2017, 1207–1214 (2017).

    Article  Google Scholar 

  36. Kim, S. M., Kim, H., Nam, Y. & Kim, S. Effects of external surface charges on the enhanced piezoelectric potential of ZnO and AlN nanowires and nanotubes. AIP Adv. 2, 042174 (2012).

    Article  CAS  Google Scholar 

  37. Weston, J. S., Harwell, J. H. & Grady, B. P. Rheological characterization of yield stress gels formed via electrostatic heteroaggregation of metal oxide nanoparticles. Soft Matter 13, 6743–6755 (2017).

    Article  CAS  Google Scholar 

  38. Lang, G. F. & Snyder, D. Understanding the physics of electrodynamic shaker performance. Sound Vib. 35, 24–33 (2001).

    Google Scholar 

  39. Wu, J. et al. Insights into the role of ferroelectric polarization in piezocatalysis of nanocrystalline BaTiO3. ACS Appl. Mater. Interfaces 10, 17842–17849 (2018).

    Article  CAS  Google Scholar 

  40. Singh, R. P. & Kundu, P. P. Thermogelation of methylcellulose from solution in N,N-dimethylformamide and characterization of the transparent gels. J. Appl. Polym. Sci. 110, 3031–3037 (2008).

    Article  CAS  Google Scholar 

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Acknowledgements

We thank M. Garg for performing the μCT imaging and S. C. W. Huang for the helpful discussion. Parts of this work were carried out at the Soft Matter Characterization Facility, the FIB-SEM facility of the University of Chicago and the SPID facility of Northwestern University’s NUANCE Center. The work was supported by AFOSR COE 5‐29168, NSF CHE‐1710116 and ARO W911NF‐17‐1‐0598 (71524‐CH). We dedicate this paper to Prof. Scott White who served as both an inspiration for this work and a personal inspiration for the authors.

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Author notes

  1. These authors contributed equally: Zhao Wang, Jun Wang.

Authors and Affiliations

  1. Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, USA

    Zhao Wang, Jun Wang, Jorge Ayarza, Tim Steeves, Saikat Manna & Aaron P. Esser‐Kahn

  2. Department of Chemistry, Northwestern University, Evanston, IL, USA

    Ziying Hu

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Contributions

Z.W., J.W., J.A. and A.P.E.-K. conceived the concept. Z.W., J.W. and A.P.E.-K. designed the experiments. Z.W., J.W., J.A., Z.H. and S.M. performed the experiments and analysed the data. T.S. conducted the finite element simulation. All authors participated in writing the manuscript.

Corresponding author

Correspondence to Aaron P. Esser‐Kahn.

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The authors declare no competing interests.

Additional information

Peer review information Nature Materials thanks Stephen Craig and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–14 and Tables 1–5.

Supplementary Video 1

Compression test of the control sample without mechanical activation.

Supplementary Video 2

Compression test of the organo-gel via mechano-chemical crosslinking.

Source data

Source Data Fig. 1

Molecular weight versus monomer conversion and GPC traces at different times.

Source Data Fig. 2

Stress–strain curves of the gel.

Source Data Fig. 3

Storage modulus change as a function of force, frequency and time.

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Wang, Z., Wang, J., Ayarza, J. et al. Bio-inspired mechanically adaptive materials through vibration-induced crosslinking. Nat. Mater. 20, 869–874 (2021). https://doi.org/10.1038/s41563-021-00932-5

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