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Network of cyano-p-aramid nanofibres creates ultrastiff and water-rich hydrospongels


The structure–property paradox of biological tissues, in which water-rich porous structures efficiently transfer mass while remaining highly mechanically stiff, remains unsolved. Although hydrogel/sponge hybridization is the key to understanding this phenomenon, material incompatibility makes this a challenging task. Here we describe hydrogel/sponge hybrids (hydrospongels) that behave as both ultrastiff water-rich gels and reversibly squeezable sponges. The self-organizing network of cyano-p-aramid nanofibres holds approximately 5,000 times more water than its solid content. Hydrospongels, even at a water concentration exceeding 90 wt%, are hard as cartilage with an elastic modulus of 50−80 MPa, and are 10–1,000 times stiffer than typical hydrogels. They endure a compressive strain above 85% through poroelastic relaxation and hydrothermal pressure at 120 °C. This performance is produced by amphiphilic surfaces, high rigidity and an interfibrillar, interaction-driven percolating network of nanofibres. These features can inspire the development of future biofunctional materials.

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Fig. 1: Conceptual images of a CY-ANF hydrospongel.
Fig. 2: Self-assembly behaviour and fibrillar structures of K-ANFs and CY-ANFs.
Fig. 3: The dual modes of a CY-ANF hydrospongel.
Fig. 4: The mechanical properties of CY-ANF hydrospongels at low strains.
Fig. 5: Mechanical compression and recovery properties of a CY-ANF hydrospongel.
Fig. 6: The viscoelastic and poroelastic relaxation times of a CY-ANF hydrospongel.

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Data availability

All relevant data supporting the findings of this study are available within the Article and its Supplementary Information, or from the corresponding authors on reasonable request. Source data are provided with this paper. They are also available via Figshare at


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H.K. acknowledges support from the KRICT Core Project (KS2342-10). D.X.O. acknowledges support from the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (2022R1C1C1003468 and 2022M3H4A1A03076577). J.P. acknowledges support from the NRF, funded by the Ministry of Science, ICT & Future Planning (2022R1C1C1004660, 2015M3D3A1A01064926 and GRDC Cooperative Hub (grant number RS-2023-00259341)). S.Y.H. acknowledges support from the NRF, funded by the Ministry of Science, ICT, & Future Planning (NRF-2022M3J4A1091450 and NRF-2021M3H4A3A02102349).

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Authors and Affiliations



M.L., H.K. and Y.E. performed the experiments and analysed the data. M.L., Y.E., H.K., J.P. and D.X.O. prepared the figures and wrote the manuscript. S.-A.P, H.J., J.M.K. and C.C. analysed the materials. M.L. and H.K. performed the hydrogel swelling tests. D.K. performed the experiments on the carbon nanotube/hydrospongel composite. T.S. contributed to conceptualizing the idea and analysis of the non-swelling behaviour. J.P. and D.X.O. conceived and designed the project. S.Y.H. managed the project finances. All authors approved the final version of the manuscript.

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Correspondence to Sung Yeon Hwang, Jeyoung Park or Dongyeop X. Oh.

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Nature Materials thanks Xinlin Tuo and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Boiling water.

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Swelling test.

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Lee, M., Kwak, H., Eom, Y. et al. Network of cyano-p-aramid nanofibres creates ultrastiff and water-rich hydrospongels. Nat. Mater. 23, 414–423 (2024).

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