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Self-healing materials with microvascular networks

Abstract

Self-healing polymers composed of microencapsulated healing agents exhibit remarkable mechanical performance and regenerative ability1,2,3, but are limited to autonomic repair of a single damage event in a given location. Self-healing is triggered by crack-induced rupture of the embedded capsules; thus, once a localized region is depleted of healing agent, further repair is precluded. Re-mendable polymers4,5 can achieve multiple healing cycles, but require external intervention in the form of heat treatment and applied pressure. Here, we report a self-healing system capable of autonomously repairing repeated damage events. Our bio-inspired coating–substrate design delivers healing agent to cracks in a polymer coating via a three-dimensional microvascular network6 embedded in the substrate. Crack damage in the epoxy coating is healed repeatedly. This approach opens new avenues for continuous delivery of healing agents for self-repair as well as other active species for additional functionality.

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Figure 1: Self-healing materials with 3D microvascular networks.
Figure 2: Mechanical behaviour and healing efficiency.
Figure 3: Grubbs’ catalyst effects on healing efficiency.

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Acknowledgements

This work has been financially supported by the Air Force Office of Scientific Research Multidisciplinary University Research Initiative (grant number F49550-05-1-0346). K.S.T. is supported in part by the Beckman Institute for Advanced Science and Technology Graduate Fellows Program. We extend our gratitude to the Imaging Technology Group at the Beckman Institute, especially S. Robinson, for assistance with scanning electron microscopy.

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Contributions

K.S.T. carried out all of the experiments and analysis. N.R.S. and S.R.W. conceived the microvascular substrate–coating experiment and directed the research. J.A.L. and S.R.W. developed the direct-write manufacturing method. J.S.M. assisted with the healing chemistry. All authors participated in discussions of the research and wrote the manuscript.

Corresponding author

Correspondence to Nancy R. Sottos.

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The authors declare no competing financial interests.

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Supplementary Information

Supplementary information, scheme 1 and figures S1-S3 (PDF 277 kb)

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Toohey, K., Sottos, N., Lewis, J. et al. Self-healing materials with microvascular networks. Nature Mater 6, 581–585 (2007). https://doi.org/10.1038/nmat1934

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