Science Advances

Supplementary Materials

The PDF file includes:

  • Supplementary Text
  • Fig. S1. Schematics of the Al2O3-CNT SNE fabrication procedure.
  • Fig. S2. Diagram and optical images of unpackaged LED chiplets (UT170-31, CREE) used in picking and placing demonstration.
  • Fig. S3. Atomic force microscopy (AFM) system used for indentation tests with external voltages.
  • Fig. S4. Adhesion on/off ratio (ratio of pull-off force with an external voltage to that without voltage) of Al2O3-coated surfaces with and without SNE on a TiN layer.
  • Fig. S5. Optical microscope images of a paper towel showing its microscopically porous and rough surface.
  • Fig. S6. Transmission electron microscopy images of Al2O3 coating on individual CNT fibers via ALD with different numbers of cycles.
  • Fig. S7. Al2O3-CNT SNEs grown with different CVD procedures, exhibiting different CNT densities.
  • Fig. S8. Pull-off forces of Al2O3-CNT SNEs with different heights according to applied voltages.
  • Fig. S9. Pull-off forces of Al2O3-CNT SNEs measured by AFM using a 4 μm Pt-coated spherical tip with different applied external voltages and preloads.
  • Fig. S10. Pull-off forces of Al2O3 coated TiN layer measured by AFM using a 4 μm Pt-coated spherical tip with different applied external voltages and preloads.
  • Fig. S11. Pull-off forces of SNE measured by AFM indentation using a 10-μm SiO2 spherical tip with and without the shear motion.
  • Fig. S12. Schematics of adhesion tests on an Al2O3-TiN surface using a microsphere.
  • Fig. S13. Contact mechanics modeling of adhesion between an Al2O3-CNT nanocomposite surface and a microsphere.
  • Fig. S14. Adhesive and gravitational forces along the object size.
  • Fig. S15. Optical microscope images of PS microspheres picked from a spin-coated layer using a patterned SNE surface and placed on a silicon wafer surface, under on or off electrical voltage conditions.
  • Fig. S16. Picking-and-placing of stainless steel (SS) microparticles, sized 15-45 μm, using a 200 μm by 200 μm Al2O3-CNT SNE, from a silicon wafer to a transparent substrate.
  • Legends for movies S1 and S2

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Other Supplementary Material for this manuscript includes the following:

  • Movie S1 (.mp4 format). Picking and placing of an unpackaged micro-LED chiplet using an Al2O3-CNT nanocomposite electroadhesive (side view).
  • Movie S2 (.mp4 format). Picking and placing of a piece of paper towel using an Al2O3-CNT nanocomposite electroadhesive and polydimethylsiloxane block.

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