Abstract
Shape morphing is vital to locomotion in microscopic organisms but has been challenging to achieve in sub-millimetre robots. By overcoming obstacles associated with miniaturization, we demonstrate microscopic electronically configurable morphing metasheet robots. These metabots expand locally using a kirigami structure spanning five decades in length, from 10 nm electrochemically actuated hinges to 100 μm splaying panels making up the ~1 mm robot. The panels are organized into unit cells that can expand and contract by 40% within 100 ms. These units are tiled to create metasheets with over 200 hinges and independent electronically actuating regions that enable the robot to switch between multiple target geometries with distinct curvature distributions. By electronically actuating independent regions with prescribed phase delays, we generate locomotory gaits. These results advance a metamaterial paradigm for microscopic, continuum, compliant, programmable robots and pave the way to a broad spectrum of applications, including reconfigurable micromachines, tunable optical metasurfaces and miniaturized biomedical devices.
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Data availability
Source data are provided with this paper. Additional data are available from the corresponding authors upon request.
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Acknowledgements
We thank E. Demaine, T. Tachi and H. Zhang for discussions and T. Pennell, J. Clark, V. Genova, G. Bordonaro and Z. Liang for technical support. This work was supported by the National Science Foundation (EFRI C3 SoRo -1935252, I.C., A.B.A., N.L.A. and H.K.-G.), the Army Research Office (W911NF-23-1-0212 and ARO W911NF-18-1-0032, I.C.), the Cornell Center for Materials Research (DMR-1719875, I.C. D.A.M. and P.L.M.), the Air Force Office of Scientific Research (MURI: FA9550-16-1-0031, P.L.M.) and the Kavli Institute at Cornell for Nanoscale Science. This work was performed, in part, at Cornell NanoScale Facility, an NNCI member supported by NSF grant NNCI-2025233. 3D imaging was performed by the Biotechnology Resource Center (BRC) Imaging Facility at the Cornell Institute of Biotechnology. Imaging data were acquired through the Cornell Institute of Biotechnology’s Imaging Facility, with NIH 1S10RR025502 funding for the shared Zeiss LSM710 confocal microscope.
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Authors and Affiliations
Contributions
Q.L., A.B.A., N.L.A., H.K.-G., P.L.M. and I.C. conceived the project. Q.L. and W.W. performed the pattern design and device fabrication. Q.L. performed the SEM imaging, confocal fluorescence microscopy imaging, electrochemical measurements and shape morphing experiments. Q.L. and W.W. conducted the locomotion experiments. H.S., I.G., Q.L. and H.K.-G. performed the simulation. J.T.P., Q.L. and I.G. analysed the shape morphing data, I.G., J.Z.K., Q.L. and M.F.R. analysed the locomotion data. P.C., Q.L. and A.B.A. developed the circuit model of addressable hinges. M.C.C., Q.L. and D.A.M. conducted the transmission electron microscopy imaging experiment. Q.L. and I.C. wrote the manuscript, with all authors contributing.
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Competing interests
Q.L., P.L.M. and I.C. are inventors on a patent application (PCT/US2021/021419) submitted by Cornell University that covers electrically programmable microscale shape-memory actuators and related robotic devices. W.W., Q.L., M.F.R., P.L.M. and I.C. are inventors on a provisional patent application (63/267,190) submitted by Cornell University that covers actuators and control electronics for cilium metasurfaces and a provisional patent application (63/368,751) submitted by Cornell University that covers integrated circuits for controlling microscopic robots. The other authors declare no competing interests.
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Nature Materials thanks Sung Kang, Metin Sitti and Jie Yin for their contribution to the peer review of this work.
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Supplementary information
Supplementary Information
Supplementary Figs. 1–16 and Notes 1–8.
Supplementary Video 1
Real-time videos showing the actuation of microsplay hinges and the unit cell of metabots. The corresponding confocal microscopy images at different voltages are also shown.
Supplementary Video 2
Real-time video of the actuation of a uniformly actuated metabot sheet.
Supplementary Video 3
Real-time videos showing the actuation of metabots with different sizes of triangular panels.
Supplementary Video 4
Real-time videos showing the actuation of a dome-shaped metabot with fixed boundary and the corresponding 3D shape imaged using confocal microscopy. Owing to the shape-memory effect of the actuators, the metabot could maintain its 3D shape even when the voltage was removed.
Supplementary Video 5
Real-time video of the actuation of metabots with square tessellations.
Supplementary Video 6
Real-time videos showing the independently actuated hinges.
Supplementary Video 7
Confocal fluorescence microscopy images showing small cap, plane and saddle shapes formed from the same pattern with different actuated areas.
Supplementary Video 8
Metabots with three or more activation zones.
Supplementary Video 9
A metabot crawling towards its head direction due to the symmetry breaking of its shape. The video has been sped up by a factor of 8.
Supplementary Video 10
A metabot without braces crawling unidirectionally.
Supplementary Video 11
A metabot with an intentionally broken hinge crawling effectively.
Source data
Source Data Fig. 2
Areal expansion ratio of the unit cell and cyclic voltammetry data plotted in Fig. 2b, and change in areal expansion ratio data plotted in Fig. 2c.
Source Data Fig. 3
Elastic energy data plotted in Fig. 3c.
Source Data Fig. 4
COM motion and area expansion ratio data plotted in Fig. 4c, COM data plotted in Fig. 4d, COM data for six different metabots plotted in Fig. 4e, histogram data between four states plotted in Fig. 4f and histogram data of the COM velocities plotted in Fig. 4g.
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Liu, Q., Wang, W., Sinhmar, H. et al. Electronically configurable microscopic metasheet robots. Nat. Mater. (2024). https://doi.org/10.1038/s41563-024-02007-7
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DOI: https://doi.org/10.1038/s41563-024-02007-7
