Theoretical strength and rubber-like behaviour in micro-sized pyrolytic carbon


The creation of materials with a combination of high strength, substantial deformability and ductility, large elastic limit and low density represents a long-standing challenge, because these properties are, in general, mutually exclusive. Using a combination of two-photon lithography and high-temperature pyrolysis, we have created micro-sized pyrolytic carbon with a tensile strength of 1.60 ± 0.55 GPa, a compressive strength approaching the theoretical limit of ~13.7 GPa, a substantial elastic limit of 20–30% and a low density of ~1.4 g cm−3. This corresponds to a specific compressive strength of 9.79 GPa cm3 g−1, a value that surpasses that of nearly all existing structural materials. Pillars with diameters below 2.3 μm exhibit rubber-like behaviour and sustain a compressive strain of ~50% without catastrophic failure; larger ones exhibit brittle fracture at a strain of ~20%. Large-scale atomistic simulations reveal that this combination of beneficial mechanical properties is enabled by the local deformation of 1 nm curled graphene fragments within the pyrolytic carbon microstructure, the interactions among neighbouring fragments and the presence of covalent carbon–carbon bonds.

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Fig. 1: Fabrication and microstructural characterization of PyC micropillars.
Fig. 2: Uniaxial compression and tension experiments on PyC micropillars.
Fig. 3: Change in strength with diameter and the ultra-large elastic limit of PyC micropillars.
Fig. 4: Atomistic simulations of the uniaxial compression and tension of PyC nanopillars.
Fig. 5: Summary of the combined ultra-high strength/specific strength and large deformability of PyC micropillars.

Data availability

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


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X.L. acknowledges financial support from the National Natural Science Foundation of China (grants 11522218 and 11720101002) and the National Basic Research of China (grant 2015CB932500). H.G. acknowledges funding from the National Science Foundation (grant DMR-1709318). J.R.G. acknowledges financial support by the US Department of Energy, Office of Basic Energy Sciences (DOE-BES) under grant DE-SC0006599. A.V. acknowledges the financial support of the Resnick Sustainability Institute at Caltech. The authors thank G. R. Rossman for assistance with Raman spectroscopy measurements, J. Yao for help with SIMS measurements and K. Narita for assistance with density measurements of pyrolytic carbon.

Author information




X.Z., X.L., H.G. and J.R.G. conceived and designed the experiments and modelling. X.Z. and A.M. synthesized the experimental samples. X.Z. performed the in situ and ex situ compression experiments. A.M. performed the in situ tension experiments. A.K. and X.Z. performed the HRTEM and EELS analyses. A.V. and L.Z. performed the Raman spectroscopy measurements. L.Z. conducted the atomistic simulations. X.Z., L.Z. and X.L. developed the model. X.Z., L.Z., X.L., H.G. and J.R.G. wrote the manuscript. All authors analysed the data, discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Huajian Gao or Julia R. Greer or Xiaoyan Li.

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The authors declare no competing interests.

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Peer review information: Nature Nanotechnology thanks Maria Pantano, Ping Xiao and other anonymous reviewer(s) for their contribution to the peer review of this work.

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Supplementary information


In situ compression of 2.25-μm-diameter PyC micropillar


In situ tension of 1.5-μm-diameter PyC micropillar


Atomistic simulation of uniaxial compression on a 20-nm-diameter PyC nanopillar


Atomistic simulation of uniaxial tension of a 20-nm-diameter PyC nanopillar

Supplementary Information

Supplementary text 1–5 Supplementary Figs. 1–20 Supplementary Figs. 1–20 Supplementary Table 1 Supplementary Table 1

Supplementary Video 1

In situ compression of 2.25-μm-diameter PyC micropillar

Supplementary Video 2

In situ tension of 1.5-μm-diameter PyC micropillar

Supplementary Video 3

Atomistic simulation of uniaxial compression on a 20-nm-diameter PyC nanopillar

Supplementary Video 4

Atomistic simulation of uniaxial tension of a 20-nm-diameter PyC nanopillar

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Zhang, X., Zhong, L., Mateos, A. et al. Theoretical strength and rubber-like behaviour in micro-sized pyrolytic carbon. Nat. Nanotechnol. 14, 762–769 (2019).

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