Research ArticleMATERIALS SCIENCE

Seamless multimaterial 3D liquid-crystalline elastomer actuators for next-generation entirely soft robots

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Science Advances  28 Feb 2020:
Vol. 6, no. 9, eaay8606
DOI: 10.1126/sciadv.aay8606
  • Fig. 1 Illustration of welding of preformed acrylate group–rich films and formation of monodomain LCE actuators and welded LCE actuators via thermal polymerization of preformed acrylate group–rich films.

    (A) Scheme of welding preformed acrylate group–rich films alone. (B) Scheme of formation of monodomain LCE actuators alone. (C) Mechanism of thermal polymerization of acrylate groups. (D) Scheme of the simultaneously “welding” and aligning processes to realize the formation of welded LCE actuators. Scale bars, 5 mm. (Photo credit: Yubai Zhang, Tsinghua University.)

  • Fig. 2 Formation and characterization of monodomain LCE actuators and their different actuation modes.

    (A) Reagents used in pre-LCE 1. (B) IR spectroscopy of pre-LCE 1 and the monodomain LCE 1. (C) XRD patterns of monodomain LCE 1 (left); monodomain LCE elongated and contracted reversibly (right). (D) Winding and unwinding of the spiral ribbon (left) and spiral spring (right). (E) Curling and uncurling (left); bending and unbending (middle); pin-shaped and flat configurations (right). (F) The actuation strain of monodomain LCE 1 before and after 1000 cycles of actuations measured by dynamic mechanical analysis (DMA). Scale bars, 5 mm. (Photo credit: Yubai Zhang, Tsinghua University.)

  • Fig. 3 Proof and illustration of formation of very complicated 3D machine- and animal-mimicking LCE actuators.

    (A) SEM images of pre-LCE 1 films before (the left two figures: scale bars, 1 mm and 200 μm) and after (the right two figures: scale bars, 1 mm and 200 μm) welding. (B) Welded reversible structures with the left part being a ribbon-like spiral reversible structure and the right part being a contraction-only reversible structure (left); two reverse ribbon-like spiral reversible structures (right). (C) Windmill-shaped reversible structure. (D) Schematic showing and photographs of a reversible fan-like structure rotating. (E) Schematic showing and photographs of a reversible eight-leg octopus-like structure stretching legs. RT, room temperature. (Photo credit: Yubai Zhang, Tsinghua University.)

  • Fig. 4 Multifunctional multimaterial LCE actuators in which different parts contain different chemical components.

    (A) Schematic showing and photographs of a multistage reversible structure. (B) Schematic showing and photographs of an area-selective reversible multiresponsive structure. Scale bars, 5 mm. (Photo credit: Yubai Zhang, Tsinghua University.)

  • Fig. 5 The chemical network of pre-LCE 5 and the multimaterial actuator made from pre-LCE 1 and pre-LCE 5.

    (A) Reagents (left) and the network structure (right) of pre-LCE 5. (B) Schematic showing and photographs of the heat-responsive multimaterial actuator made from pre-LCE 1 and pre-LCE 5 (left); illustration of welding from pre-LCE 1 and pre-LCE 5 (right). Scale bars, 5 mm. (Photo credit: Yubai Zhang, Tsinghua University.)

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/6/9/eaay8606/DC1

    Fig. S1. Proof of the formation of pre-LCE 1.

    Fig. S2. Additional characterizations of polydomain LCE 1.

    Fig. S3. The intensity versus azimuthal angle figure of monodomain LCE 1.

    Fig. S4. POM images of monodomain LCE 1 at room temperature being rotated at the interval of 45°.

    Fig. S5. Additional proof of welding.

    Fig. S6. Fabrication method of 3D machine- and animal-mimicking LCE robots.

    Fig. S7. The modulus-temperature and tan δ–temperature curves of polydomain LCE 2 and polydomain LCE 3.

    Fig. S8. Photothermal effect of combined structure contained pre-LCE 1 and pre-LCE 4.

    Fig. S9. Proof of successful welding of pre-LCE 1 and pre-LCE 5.

    Fig. S10. Welding of pre-LCE 1 and pre-LCE 6.

    Movie S1. The temperature-responsive (from 30° to 100°C) rotation of the 3D fan-shaped reversible LCE structure.

    Movie S2. The inverse temperature-responsive (from 100° to 30°C) rotation of the 3D fan-shaped reversible LCE structure.

    Movie S3. The 3D octopus-imitating reversible robot uncurling legs upon temperature change from 30° to 100°C.

    Movie S4. The 3D octopus-imitating reversible robot curling legs upon temperature change from 100° to 30°C.

    Movie S5. The composite reversible structure made of LCE 1 (without polydopamine) and LCE 4 (with polydopamine) responding to IR light.

  • Supplementary Materials

    The PDF file includes:

    • Fig. S1. Proof of the formation of pre-LCE 1.
    • Fig. S2. Additional characterizations of polydomain LCE 1.
    • Fig. S3. The intensity versus azimuthal angle figure of monodomain LCE 1.
    • Fig. S4. POM images of monodomain LCE 1 at room temperature being rotated at the interval of 45°.
    • Fig. S5. Additional proof of welding.
    • Fig. S6. Fabrication method of 3D machine- and animal-mimicking LCE robots.
    • Fig. S7. The modulus-temperature and tan δ–temperature curves of polydomain LCE 2 and polydomain LCE 3.
    • Fig. S8. Photothermal effect of combined structure contained pre-LCE 1 and pre-LCE 4.
    • Fig. S9. Proof of successful welding of pre-LCE 1 and pre-LCE 5.
    • Fig. S10. Welding of pre-LCE 1 and pre-LCE 6.

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). The temperature-responsive (from 30° to 100°C) rotation of the 3D fan-shaped reversible LCE structure.
    • Movie S2 (.mp4 format). The inverse temperature-responsive (from 100° to 30°C) rotation of the 3D fan-shaped reversible LCE structure.
    • Movie S3 (.mp4 format). The 3D octopus-imitating reversible robot uncurling legs upon temperature change from 30° to 100°C..
    • Movie S4 (.mp4 format). The 3D octopus-imitating reversible robot curling legs upon temperature change from 100° to 30°C.
    • Movie S5 (.mp4 format). The composite reversible structure made of LCE 1 (without polydopamine) and LCE 4 (with polydopamine) responding to IR light.

    Files in this Data Supplement:

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