Science Robotics

Supplementary Materials

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  • Fig. S1. Scanning electron microscopy (SEM) image of Ni nanowires, 200 nm in diameter and 8 to 10 μm in length.
  • Fig. S2. Characterization of the alignment of Ni nanowires during the two-step polymerization by optical microscopy.
  • Fig. S3. Optical microscope images of SP1 hydrogel-metal hybrid materials with rotating magnetic field (0.5 Hz, 15.0 mT, rotating in the y-z plane) off (left) and on (right).
  • Fig. S4. Characterization of the alignment of Ni nanowires embedded in the hydrogel using optical and scanning electron microscopy.
  • Fig. S5. Characterization of unaligned Ni nanowires embedded in the hydrogel matrix.
  • Fig. S6. Characterization of chained up Ni nanoparticles embedded in the hydrogel matrix.
  • Fig. S7. Superconducting quantum interference device (SQUID) measurements of different hydrogels.
  • Fig. S8. Volume change by light irradiation.
  • Fig. S9. Reversibility test of photo-actuation.
  • Fig. S10. Linear regime of the magnetic response of the Ni nanowires.
  • Fig. S11. Calibration of the elastic parameters from the DMA measurement after light irradiation.
  • Fig. S12. Benchmark of the fiber-reinforced magnetoelastic model using numerical and analytical solutions.
  • Fig. S13. Characterization of mechanical properties for hydrogel film samples after equilibrated in 5 mM HCl in the dark with Ni nanowires (0.5 wt %) aligned parallel or perpendicular to the plane of the films.
  • Fig. S14. Plot of G′ and G″ of samples before and after photo-actuation.
  • Fig. S15. Light-induced bending directions of the hydrogel squares (10 mm × 10 mm × 0.5 mm, L × W × T) containing aligned Ni nanowires (0.5 wt %) were affected by the mechanical anisotropy caused by the aligned Ni nanowires.
  • Fig. S16. Photographs of control hydrogels containing chained up Ni nanoparticles or unaligned Ni nanowires under the same magnetic fields.
  • Fig. S17. Optimization of the length of stabilizing arms.
  • Fig. S18. Absorbance spectra of SP1 and SP2 upon light irradiation.
  • Fig. S19. Absorbance spectra of SP1 and SP2 in the dark.
  • Fig. S20. Measured bending angle of hydrogels with varying light intensities.
  • Fig. S21. Measured leg span and walking speed of hydrogels containing SP1 and SP2 as a function of irradiation time.
  • Fig. S22. Hydrogel objects containing SP1 moiety bend up gradually controlled by programmed sequences of light intensity (48 to 192 mW/cm2) irradiating from the bottom and flatten when light is off.
  • Fig. S23. Hydrogel objects containing SP2 moiety bend up in 5 min when irradiating with a bottom light (4.7 mW/cm2) and gradually flatten when irradiating with stronger light (14.1, 23.5 mW/cm2) because of the elimination of hydrophobicity gradient.
  • Fig. S24. Preparation of hydrogel objects with different alignment directions.
  • Fig. S25. Measurement of possible photothermal effect and photobleaching after irradiation with a strong light for 10 s.
  • Fig. S26. Effect of magnetic field on the photo-actuation.
  • Legends for movies S1 to S10
  • References (4450)

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Other Supplementary Material for this manuscript includes the following:

  • Movie S1 (.mp4 format). Photo-actuation and walking motion of hydrogel-metal hybrids containing the SP1 moiety.
  • Movie S2 (.mp4 format). Effects of stabilizing arm length on walking gait of hydrogel-metal hybrids containing the SP1 moiety.
  • Movie S3 (.mp4 format). Effects of magnetic field strength and frequency on walking gait of the hydrogel-metal hybrids containing the SP1 moiety.
  • Movie S4 (.mp4 format). Walking gait of hydrogel-metal hybrids (SP1) with a reduced size.
  • Movie S5 (.mp4 format). Steering motion of the hydrogel-metal hybrids made of SP1 from experiment (left) and simulation (right).
  • Movie S6 (.mp4 format). Path following of hydrogel-metal hybrids from both simulation and experiment.
  • Movie S7 (.mp4 format). Chemical design and bimodal control of hydrogel-metal hybrids.
  • Movie S8 (.mp4 format). Walking gait of hydrogel-metal hybrids made of SP1 containing diagonally aligned and perpendicularly aligned Ni nanowires.
  • Movie S9 (.mp4 format). Climbing an inclined surface by hydrogel-metal hybrids made of SP1.
  • Movie S10 (.mp4 format). Cargo capture, transport, and release by hydrogel-metal hybrids made of SP1.

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