Research ArticleAPPLIED SCIENCES AND ENGINEERING

Self-organization of maze-like structures via guided wrinkling

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Science Advances  30 Jun 2017:
Vol. 3, no. 6, e1700071
DOI: 10.1126/sciadv.1700071
  • Fig. 1 Guided wrinkling for maze construction.

    (A) Self-organization of maze-like structures through wrinkling. (B) Schematic illustration of the fabrication process using ridge-guiding structures. First, the guiding structure composed of a groove array was prepatterned on the microparticle surface through the photopolymerization of the photocurable polymer with the corresponding photomask. Then, each ridge decision point was randomly transformed to either an ending, a bend, a straight line, or a bifurcation type during the wrinkling. According to the geometry of the ridge-guided site, wrinkles were spatially aligned in predetermined directions. (C) Bright-field and fluorescence image of the prepatterned substrate. The prepatterned microparticle immersed in ethanol was imaged by a CLSM. Dashed lines represent the ridge-guided site. Scale bar, 10 μm. (D) Bright-field and fluorescence image of the wrinkled microparticle. Each dot and its color in the fluorescence image represent a ridge decision point and its type shown in (B), respectively. Scale bar, 10 μm.

  • Fig. 2 Controlling maze tessellation.

    (A to C) CLSM images of the wrinkle patterns designed for orthogonal, sigma, and theta maze tessellations, respectively. The inset images show a part of the photomask for each pattern. Scale bars, 25 μm. (D to F) Distributions of the ridge orientation extracted from images with orthogonal, sigma, and theta tessellations, respectively. Each histogram contains ridge information from 20 microparticles.

  • Fig. 3 Controlling the degree of ridge confinement along guiding structures.

    (A) Confinement of the ridge straightness based on the guiding structure dimensions. Photomasks for guiding structures were designed to satisfy several ratios between the characteristic wavelength (λ) and the dimensions of the ridge-guiding structure (dx and dy). The exact (dx/λ, dy/λ) values for the displayed CLSM images were (0.25, 0.25), (0.43, 0.22), (0.86, 0.22), (2.07, 0.26), (0.52, 0.52), (0.90, 0.45), (1.83, 0.46), (0.91, 0.91), (1.84, 0.92), and (1.83, 1.83) from the bottom left image, respectively. Scale bar, 10 μm. (B) Confinement of the pattern wavelength based on the guiding structure dimensions. The ratios between the characteristic wavelength and the constrained wavelength (λ′) were extracted from the sample patterns guided with several dx/λ values satisfying dy/λ < 0.25. Error bars represented SDs, and n = 7 particles for each data point. Insets show representative patterns at the marked points. Scale bar, 10 μm.

  • Fig. 4 Demonstration of various physical mazes.

    (A) Theta maze. Maze paths (lower image) were analyzed from the CLSM image (upper image). The starting point (red dot), the ending point (green dot), and the possible pathways (lines) are presented. The red line shows the shortest solution path. Scale bar, 25 μm. (B) Mixed maze. Wrinkles with four different directional orders (including random and anisotropic patterns) were generated in a single structure for a complex maze pattern. Scale bar, 25 μm. (C) Orthogonal maze containing a customized internal structure. Letter-shaped walls were fabricated in the middle of the maze without destroying the orthogonal maze pattern. Scale bar, 25 μm.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1700071/DC1

    fig. S1. Comparative analysis of the orthogonal ridge pattern in different generation methods.

    fig. S2. Scanning electron microscopy image of a maze microparticle (scale bar, 10 μm).

    fig. S3. Uniqueness of orthogonal patterns.

    fig. S4. Ridge organization in a sigma tessellation.

    fig. S5. Microparticle design for studying the guiding effect.

    fig. S6. Controlling the anisotropic structure.

    fig. S7. Inscribing letters with wrinkles.

    fig. S8. Control of the code complexity.

    movie S1. Generation of the guided wrinkles.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Comparative analysis of the orthogonal ridge pattern in different generation methods.
    • fig. S2. Scanning electron microscopy image of a maze microparticle (scale bar, 10 μm).
    • fig. S3. Uniqueness of orthogonal patterns.
    • fig. S4. Ridge organization in a sigma tessellation.
    • fig. S5. Microparticle design for studying the guiding effect.
    • fig. S6. Controlling the anisotropic structure.
    • fig. S7. Inscribing letters with wrinkles.
    • fig. S8. Control of the code complexity.
    • Legend for movie S1

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    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.avi format). Generation of the guided wrinkles.

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