2D Mechanical Metamaterials with Widely Tunable Unusual Modes of Thermal Expansion

Xiaoyue Ni, Xiaogang Guo, Jiahong Li, Yonggang Huang, Yihui Zhang*, John A. Rogers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

84 Scopus citations


Most natural materials expand uniformly in all directions upon heating. Artificial, engineered systems offer opportunities to tune thermal expansion properties in interesting ways. Previous reports exploit diverse design principles and fabrication techniques to achieve a negative or ultralow coefficient of thermal expansion, but very few demonstrate tunability over different behaviors. This work presents a collection of 2D material structures that exploit bimaterial serpentine lattices with micrometer feature sizes as the basis of a mechanical metamaterials system capable of supporting positive/negative, isotropic/anisotropic, and homogeneous/heterogeneous thermal expansion properties, with additional features in unusual shearing, bending, and gradient modes of thermal expansion. Control over the thermal expansion tensor achieved in this way provides a continuum-mechanics platform for advanced strain-field engineering, including examples of 2D metamaterials that transform into 3D surfaces upon heating. Integrated electrical and optical sources of thermal actuation provide capabilities for reversible shape reconfiguration with response times of less than 1 s, as the basis of dynamically responsive metamaterials.

Original languageEnglish (US)
Article number1905405
JournalAdvanced Materials
Issue number48
StatePublished - Nov 1 2019


  • bimaterial lattices
  • programmable metamaterials
  • strain-field engineering
  • tunable thermal properties
  • unusual thermal expansion

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • General Materials Science


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