Letter | Published:

Orientational order of motile defects in active nematics

Nature Materials volume 14, pages 11101115 (2015) | Download Citation

Abstract

The study of liquid crystals at equilibrium has led to fundamental insights into the nature of ordered materials, as well as to practical applications such as display technologies. Active nematics are a fundamentally different class of liquid crystals, driven away from equilibrium by the autonomous motion of their constituent rod-like particles1,2,3,4. This internally generated activity powers the continuous creation and annihilation of topological defects, which leads to complex streaming flows whose chaotic dynamics seem to destroy long-range order5,6,7,8,9,10,11. Here, we study these dynamics in experimental and computational realizations of active nematics. By tracking thousands of defects over centimetre-scale distances in microtubule-based active nematics, we identify a non-equilibrium phase characterized by a system-spanning orientational order of defects. This emergent order persists over hours despite defect lifetimes of only seconds. Similar dynamical structures are observed in coarse-grained simulations, suggesting that defect-ordered phases are a generic feature of active nematics.

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Acknowledgements

The experimental portion of this study was primarily supported by the Department of Energy, Office of Basic Energy Sciences, through award DE-SC0010432TDD (S.J.D. and Z.D.). The computational portion of this work (G.S.R., M.F.H. and A.B.) was supported by NSF-MRSEC-1420382 and NSF-DMR-1149266. Computational resources were provided by the NSF through XSEDE (Stampede and Trestles) and the Brandeis HPCC, which is partially supported by the Brandeis MRSEC (NSF-MRSEC-1420382). We acknowledge the use of a MRSEC optical and biosynthesis facility supported by NSF-MRSEC-1420382.

Author information

Author notes

    • Stephen J. DeCamp
    •  & Gabriel S. Redner

    These authors contributed equally to this work.

Affiliations

  1. Department of Physics, Brandeis University, Waltham, Massachusetts 02454, USA

    • Stephen J. DeCamp
    • , Gabriel S. Redner
    • , Aparna Baskaran
    • , Michael F. Hagan
    •  & Zvonimir Dogic

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Contributions

S.J.D. and Z.D. conceived the experiments and G.S.R., A.B. and M.F.H. conceived the simulations. S.J.D. acquired experimental data. G.S.R. performed computer simulations. S.J.D. and G.S.R. analysed defect dynamics. S.J.D., G.S.R., A.B., M.F.H. and Z.D. wrote the paper. All authors revised the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Michael F. Hagan or Zvonimir Dogic.

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DOI

https://doi.org/10.1038/nmat4387

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