Self-healing of electrical damage in polymers using superparamagnetic nanoparticles


High-voltage power transmission in electrical grids requires reliable and durable dielectric polymers for wire insulation1,2. Electrical treeing caused by high, local electric fields is a damaging process that leads to structure degradation and electrical conduction of dielectric materials, and ultimately, to catastrophic failure of the devices3,4,5. Here, we demonstrate that the addition of less than 0.1 volume per cent of superparamagnetic nanoparticles into a thermoplastic polymer enables the repair of regions damaged by electrical treeing and the restoration of the insulating properties. Under the application of an oscillating magnetic field, the embedded nanoparticles migrate to the electrical trees and generate a higher local temperature, which heals the electrical tree channels in the polymer. Our method allows us to regenerate the dielectric strength and electrical resistivity over multiple cycles of tree formation and healing, which could be used to increase the lifespan and sustainability of power cables for electronics and energy applications.

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Fig. 1: Healing of electrical trees.
Fig. 2: Migration and diffusion of the nanoparticles during the healing process.
Fig. 3: Electrical ageing and restoration of electrical properties of the polymer.
Fig. 4: Electrical ageing/healing cycles and tree inception voltages of the polymer.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.


  1. 1.

    Dissado, L. A. & Fothergill, J. C. Electrical Degradation and Breakdown in Polymers (IET, London, 1992).

  2. 2.

    Tanaka, T., Okamoto, T., Nakanishi, K. & Miyamoto, T. Aging and related phenomena in modern electric-power systems. IEEE Trans. Electr. Insul. 28, 826–844 (1993).

    CAS  Article  Google Scholar 

  3. 3.

    Bamji, S. S., Bulinski, A. T., Chen, Y. & Densley, R. J. Threshold voltage for electrical tree inception in underground HV transmission cables. IEEE Trans. Electr. Insul. 27, 402–404 (1992).

    Article  Google Scholar 

  4. 4.

    Shimizu, N. & Laurent, C. Electrical tree initiation. IEEE Trans. Electr. Insul. 5, 651–659 (1998).

    Article  Google Scholar 

  5. 5.

    Dissado, L. A., Dodd, S. J., Champion, J. V., Williams, P. I. & Alison, J. M. Propagation of electrical tree structures in solid polymeric insulation. IEEE Trans. Dielect. Electr. Insul. 4, 259–279 (1997).

    CAS  Article  Google Scholar 

  6. 6.

    Jarvid, M. et al. A new application area for fullerenes: voltage stabilizers for power cable insulation. Adv. Mater. 27, 897–902 (2015).

    CAS  Article  Google Scholar 

  7. 7.

    Cherney, E. A. Nanodielectrics applications—today and tomorrow. IEEE Electr. Insul. Mag. 29, 59–65 (2013).

    Article  Google Scholar 

  8. 8.

    Salvatierra, L. M. et al. Self-healing during electrical treeing: a feature of the two-phase liquid–solid nature of silicone gels. IEEE Trans. Dielect. Electr. Insul. 23, 757–767 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    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).

    CAS  Article  Google Scholar 

  10. 10.

    Blaiszik, B. J. et al. Self-healing polymers and composites. Annu. Rev. Mater. Res. 40, 179–211 (2010).

    CAS  Article  Google Scholar 

  11. 11.

    Xing, L. et al. Self-healable polymer nanocomposites capable of simultaneously recovering multiple functionalities. Adv. Funct. Mater. 26, 3524 (2016).

    CAS  Article  Google Scholar 

  12. 12.

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

    CAS  Article  Google Scholar 

  13. 13.

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

    CAS  Article  Google Scholar 

  14. 14.

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

    CAS  Article  Google Scholar 

  15. 15.

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

    CAS  Article  Google Scholar 

  16. 16.

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

    CAS  Article  Google Scholar 

  17. 17.

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

    CAS  Article  Google Scholar 

  18. 18.

    White, S. R. et al. Restoration of large damage volumes in polymers. Science 344, 620–623 (2014).

    CAS  Article  Google Scholar 

  19. 19.

    Li, J. Y., Zhang, L. & Ducharme, S. Electric energy density of dielectric nanocomposites. Appl. Phys. Lett. 90, 132901 (2007).

    Article  Google Scholar 

  20. 20.

    Corten, C. C. & Urban, M. W. Repairing polymers using oscillating magnetic field. Adv. Mater. 21, 5011–5015 (2009).

    CAS  Article  Google Scholar 

  21. 21.

    Yoonessi, M. et al. Self-healing of core-shell magnetic polystyrene nanocomposites. ACS Appl. Mater. Interfaces 7, 16932–16937 (2015).

    CAS  Article  Google Scholar 

  22. 22.

    Ahmed, A. S. & Ramanujan, R. V. Magnetic field triggered multicycle damage sensing and self healing. Sci. Rep. 5, 13773 (2015).

    Article  Google Scholar 

  23. 23.

    Gupta, S., Zhang, Q., Emrick, T., Balazs, A. C. & Russell, T. P. Entropy-driven segregation of nanoparticles to cracks in multilayered composite polymer structures. Nat. Mater. 5, 229–233 (2006).

    Article  Google Scholar 

  24. 24.

    Lee, J. Y., Buxton, G. A. & Balazs, A. C. Using nanoparticles to create self-healing composites. J. Chem. Phys. 121, 5531–5540 (2004).

    CAS  Article  Google Scholar 

  25. 25.

    Balazs, A. C., Emrick, T. & Russell, T. P. Nanoparticle polymer composites: where two small worlds meet. Science 314, 1107–1110 (2006).

    CAS  Article  Google Scholar 

  26. 26.

    Fortin, J. et al. Size-sorted anionic iron oxide nanomagnets as colloidal mediators for magnetic hyperthermia. J. Am. Chem. Soc. 129, 2628–2635 (2007).

    CAS  Article  Google Scholar 

  27. 27.

    Kim, Y. H. & Wool, R. P. A theory of healing at a polymer–polymer interface. Macromolecules 16, 1115–1120 (1983).

    CAS  Article  Google Scholar 

  28. 28.

    Stone, G. C. Partial discharge diagnostics and electrical equipment insulation condition assessment. IEEE Trans. Electr. Insul. 12, 891–904 (2005).

    Article  Google Scholar 

  29. 29.

    Kim, H. et al. Coil design and measurements of automotive magnetic resonant wireless charging system for high-efficiency and low magnetic field leakage. IEEE Trans. Microw. Theory 2, 383–400 (2016).

    Google Scholar 

  30. 30.

    Schneider, P. E., Horio, M. & Lorenz, R. D. Evaluation of point field sensing in IGBT modules for high-bandwidth current measurement. IEEE Trans. Ind. Appl. 49, 1430–1437 (2013).

    Article  Google Scholar 

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This work was supported by the Program of National Key Basis and Development Plan (973) (grant 2014CB239505 to J. He). The scanning transmission electron microscopy was performed in Beijing Neurosurgical Institute (China). The authors thank C.J. Cao (Carl Zeiss Co. Ltd, Shanghai, China) for sample mounting method and imaging technology support in the computed micro-X-ray tomography tests, and Z.X. Cao (Object Research Systems Inc., Montreal, Canada) for assistance with 3D reconstruction and analysis.

Author information




J. He, Q.L., Q.W. and Y.Y. conceived and designed the experiments. Y.Y., Q.L., L.G. and J. Hu carried out the experiments. Y.Y. and J.Q. performed simulations. Y.Y., J. He, Q.L., R.Z., Q.W. and S.X.W. analysed the data. Q.L., Q.W. and J.He wrote the manuscript. All authors discussed the results and commented on the manuscript.

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Correspondence to Jinliang He or Qi Li or Qing Wang.

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Supplementary Figures 1–19 Supplementary Table 1–7

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Yang, Y., He, J., Li, Q. et al. Self-healing of electrical damage in polymers using superparamagnetic nanoparticles. Nature Nanotech 14, 151–155 (2019).

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