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Rapid self-strengthening in double-network hydrogels triggered by bond scission

Nature Materials volume 24, pages 607–614 (2025)Cite this article

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Abstract

The scission of chemical bonds in materials can lead to catastrophic failure, with weak bonds typically undermining the materials’ strength. Here we demonstrate how weak bonds can be leveraged to achieve self-strengthening in polymer network materials. These weak sacrificial bonds trigger mechanochemical reactions, forming new networks rapidly enough to reinforce the material during deformation and significantly improve crack resistance. This rapid strengthening exhibits strong rate dependence, dictated by the interplay between bond breaking and the kinetics of force-induced network formation. As the network formation is generally applicable to diverse monomers and crosslinkers with different kinetics, a wide range of mechanical properties can be obtained. These findings may inspire the design of tough polymer materials with on-demand, rate-dependent mechanical behaviours through mechanochemistry, broadening their applications across various fields.

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Fig. 1: Conceptual scheme of strengthening via bond scission-triggered rapid network formation in DN hydrogels.
Fig. 2: Self-strengthening of DN-DAC hydrogels in tensile test.
Fig. 3: Rate-dependent crack reinforcement of DN-DAC hydrogels in single-edge notched test.
Fig. 4: Crack propagation behaviour of DN-DAC gels in pure shear test and trouser tear test.

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Data supporting this study are provided as Source data or included in Supplementary Information. Source data are provided with this paper.

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Acknowledgements

J.P.G. and T.N. acknowledge the funding support from JSPS KAKENHI (grant nos. JP22H04968, JP22K21342 and JP24H00848), JST FOREST (grant no. JPMJFR221X) and JST PRESTO (grant no. JPMJPR2098), Japan. M.R. acknowledges financial support of the NSF Center for the Chemistry of Molecularly Optimized Networks (MONET), CHE-2116298.

Author information

Authors and Affiliations

  1. Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan

    Zhi Jian Wang, Wei Li, Tasuku Nakajima, Michael Rubinstein & Jian Ping Gong

  2. Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan

    Xueyu Li, Tasuku Nakajima & Jian Ping Gong

  3. Thomas Lord Department of Mechanical Engineering and Materials Science, Departments of Chemistry, Department of Physics, and Department of Biomedical Engineering, Duke University, Durham, NC, USA

    Michael Rubinstein

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  1. Zhi Jian Wang
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  2. Wei Li
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  3. Xueyu Li
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  4. Tasuku Nakajima
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  5. Michael Rubinstein
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  6. Jian Ping Gong
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Contributions

Z.J.W. and J.P.G. conceived the study, and Z.J.W. performed all of the experiments. X.L. helped in the experiments. W.L. and M.R. performed the simulations. All authors contributed to the discussion. T.N. and J.P.G. supervised the study. Z.J.W., W.L. and J.P.G. wrote the paper with input from all authors.

Corresponding authors

Correspondence to Michael Rubinstein or Jian Ping Gong.

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The authors declare no competing interests.

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Peer review information

Nature Materials thanks Ximin He 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. 1–28, Tables 1 and 2, and discussion.

Supplementary Video 1

Uniaxial tensile test of DN-H2O and DN-DAC.

Supplementary Video 2

Single-edge notched test of DN-H2O and DN-DAC.

Supplementary Video 3

Pure shear test of DN-H2O and DN-DAC.

Supplementary Video 4

Trouser tear test of DN-H2O and DN-DAC.

Source data

Source Data Fig. 2

Statistical source data.

Source Data Fig. 3

Statistical source data.

Source Data Fig. 4

Statistical source data.

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Wang, Z.J., Li, W., Li, X. et al. Rapid self-strengthening in double-network hydrogels triggered by bond scission. Nat. Mater. 24, 607–614 (2025). https://doi.org/10.1038/s41563-025-02137-6

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