Article | Published:

Approaching theoretical strength in glassy carbon nanolattices

Nature Materials volume 15, pages 438443 (2016) | Download Citation

Abstract

The strength of lightweight mechanical metamaterials, which aim to exploit material-strengthening size effects by their microscale lattice structure, has been limited by the resolution of three-dimensional lithography technologies and their restriction to mainly polymer resins. Here, we demonstrate that pyrolysis of polymeric microlattices can overcome these limitations and create ultra-strong glassy carbon nanolattices with single struts shorter than 1 μm and diameters as small as 200 nm. They represent the smallest lattice structures yet produced—achieved by an 80% shrinkage of the polymer during pyrolysis—and exhibit material strengths of up to 3 GPa, corresponding approximately to the theoretical strength of glassy carbon. The strength-to-density ratios of the nanolattices are six times higher than those of reported microlattices. With a honeycomb topology, effective strengths of 1.2 GPa at 0.6 g cm−3 are achieved. Diamond is the only bulk material with a notably higher strength-to-density ratio.

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Acknowledgements

The authors thank M. Madou for stimulating discussions introducing us to the concept of pyrolysis of resist structures. Financial support of this work by the Robert Bosch-Foundation is gratefully acknowledged.

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Affiliations

  1. Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany

    • J. Bauer
    • , A. Schroer
    • , R. Schwaiger
    •  & O. Kraft

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Contributions

J.B. and O.K. designed the research; J.B. designed structures; J.B. and A.S. manufactured samples; J.B., performed ex situ measurements; J.B. and R.S. performed in situ measurements; J.B. performed analytical and finite element calculations; J.B., O.K. and R.S. analysed data; J.B. wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to J. Bauer.

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https://doi.org/10.1038/nmat4561

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