Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling

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Science  09 Jan 2015:
Vol. 347, Issue 6218, pp. 154-159
DOI: 10.1126/science.1260960
  • Fig. 1 Process for deterministic assembly of 3D mesostructures of monocrystalline silicon from 2D precursors.

    (A) Finite-element analysis (FEA) results that correspond to the formation of 3D conical helices from 2D filamentary serpentine ribbons of silicon bonded at selected points (red dots) to a stretched slab of silicone elastomer. Compressive forces induced by relaxing the strain in the elastomer lead to coordinated out-of-plane buckling, twisting, and translational motions in the silicon, yielding 3D mesostructures. The scanning electron microscope (SEM) images at the lower right show an experimental result. (B) Schematic diagram of a 2D silicon precursor and its bonding sites (top), an SEM image of a single-helical coil formed from this precursor (left), and corresponding FEA prediction (right). (C and D) Similar results for a dual-helix coil (C) and a nested, coaxial pair of connected helical coils (D). (E) SEM image with overlaid FEA prediction of helical coils with right- and left-handed chirality, on the left and right sides of the dashed red line, respectively. (F) SEM image with overlaid FEA prediction of structures whose chirality changes abruptly at the locations defined by the dashed red line. (G) SEM images and FEA predictions of a complex 3D mesostructure formed from a 2D precursor that consists of closed-loop circular filamentary serpentines and radially oriented ribbons, selectively bonded to a biaxially stretched elastomer substrate. In all cases, the color in the FEA results corresponds to the maximum principal strains. Scale bars, 400 μm.

  • Fig. 2 Experimental and computational studies of various 3D mesostructures and classification according to their modes of deformation.

    (A) Average curvature components and mode ratio of a 3D mesostructure (3D wavy ribbon) that involves only bending, as a function of prestrain in the stretched assembly platform. (B) Similar results for a 3D mesostructure (3D single-helical coil) that involves both bending and twisting. Dots represent FEA results; solid lines represent the scaling law Embedded Image. The colors in the 3D FEA correspond to the maximum principal strains. (C and D) 2D precursors, mode ratios, optical micrographs, and FEA predictions for 18 3D mesostructures that exhibit bending-dominated modes (C) and bending-twisting mixed modes (D). Scale bars, 200 μm.

  • Fig. 3 3D mesostructures with multilevel configurations and/or extended network architectures.

    (A) 2D precursors, FEA predictions, and optical micrographs for six 3D mesostructures that have double- or triple-level configurations. (B) Distributed 3D mesoscale networks comprising interconnected collections of the 3D structures in Figs. 2 and 3A. Scale bars, 200 μm (A), 400 μm (B).

  • Fig. 4 3D structures with various material compositions and feature sizes, and results for electrical behaviors in a tunable 3D toroidal inductor.

    (A) Experimental images and overlaid FEA predictions of 3D mesostructures made of metal (Ni), polymer [photodefinable epoxy (SU8) and polyimide (PI)], and heterogeneous combinations of materials (Au and SU8). Scale bars, 500 μm. (B) 3D mesostructures of silicon with lateral dimensions and thicknesses in the submicrometer regime, with overlaid FEA predictions. Scale bars, 5 μm. (C) 3D mesostructure of silicon in its as-fabricated state (left column) and in a configuration that results from uniaxially stretching the substrate (right column), all with overlaid FEA predictions. Scale bars, 50 μm. (D) Measured and computed frequency dependence of the inductance and the Q factor of a single 3D toroidal inductor mechanically configured into two different shapes by partial (21%, in an absolute sense, of an original prestrain of 54%; blue) and then complete release of prestrain (red), along with the corresponding 2D precursor (green) as reference. The panels on the right show simulated magnetic field distributions of these structures for feed-in power of 1 W. The arrows indicate direction and their colors indicate magnitude.

Additional Files

  • Assembly of micro/nanomaterials into complex, three-dimensional architectures by compressive buckling

    Sheng Xu, Zheng Yan, Kyung-In Jang, Wen Huang, Haoran Fu, Jeonghyun Kim, Zijun Wei, Matthew Flavin, Joselle McCracken, Renhan Wang, Adina Badea, Yuhao Liu, Dongqing Xiao, Guoyan Zhou, Jungwoo Lee, Ha Uk Chung, Huanyu Cheng, Wen Ren, Anthony Banks, Xiuling Li, Ungyu Paik, Ralph G. Nuzzo, Yonggang Huang, Yihui Zhang, John A. Rogers

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S23

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