Research ArticleMATERIALS SCIENCE

Phase behaviors of colloidal analogs of bent-core liquid crystals

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Science Advances  11 May 2018:
Vol. 4, no. 5, eaas8829
DOI: 10.1126/sciadv.aas8829
  • Fig. 1 Schematic illustration of the four typical LC phases assembled from BRs.

    (A) Schematic illustrations of the geometric and orientational parameters of BRs and the assembled SmC, SmA, SmCSPA, and TSm phases. The parameters, such as layer normal n, tilt direction t, and orientational axis p, define the chirality of the formed TSm phase. (B) Sediment of BRs dispersed in DMSO in a capillary tube. (C and D) Representative low (C) and high (D) magnification POM images of BRs with TSm phase in planar capillary. The spacing between two neighboring disclination lines [dotted lines in (D)] corresponds to Embedded ImageP. Scale bars, 200 μm (C) and 20 μm (D).

  • Fig. 2 BRs with different geometries and corresponding LC phases.

    (A to D) SEM images of representative rods with different α and L/D: (A) rod with α = 0° and L/D = 3.5, (B) BR with α = 15° and L/D = 3.8, (C) BR with α = 37° and L/D = 7.2, and (D) BR with α = 48° and L/D = 10.0. Insets in (A) to (D) are corresponding schematic illustrations of BRs. (E to L) POM images (E to H) and SEM images (I to L) of corresponding LC phases assembled from rods in (A) to (D): (E and I) SmC phase of rod in (A), (F and J) SmA phase of rod in (B), (G and K) SmCSPA phase of rod in (C), and (H and L) TSm phase of rod in (D). Insets in (E) to (H) are corresponding schematic illustrations of LC phases. Scale bars, 1 μm (A to D), 10 μm (E to H), and 4 μm (I to L).

  • Fig. 3 Effect of BR geometry on experimental phase diagram.

    (A) Experimental phase diagram of symmetric BRs as a function of α and L/D. The dashed lines indicate superficial boundaries between phases. (B) Tilt angle θ as a function of α and L/D of BRs in the SmCSPA phase.

  • Fig. 4 LC phases observed in Brownian dynamics simulations.

    Simulation results of LC phases assembled from rods (A to D) with L/D = 4 but different α: (A) rod with α = 0° in SmC phase, (B) rod with α = 10° in SmA phase, (C) rod with α = 25° in SmCSPA phase, and (D) rod with α = 50° in isotropic phase; rods (E and F) with the same α as rod in (D): (E) rod with L/D = 6 in SmCSPA phase and (F) rod with L/D = 10 in TSm phase. (G) The orientation parameter χ varies with α of the BRs with L/D = 8.

  • Fig. 5 Phase diagram given by simulations.

    Simulation phase diagram of symmetric BRs as a function of α and L/D. The solid lines are drawn to guide the eye on boundaries between phases.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/5/eaas8829/DC1

    fig. S1. SEM images of representative BRs with different geometries.

    fig. S2. SEM images of representative asymmetric BRs with different geometries.

    fig. S3. Sedimentation of BRs.

    fig. S4. Volume fraction of BRs in the bottom ordered phase.

    fig. S5. Flow feature of the LC phase.

    fig. S6. Shear-induced LC formation.

    fig. S7. POM images showing the long-range ordering of BRs in the SmCSPA phase.

    fig. S8. Optical activity of the TSm phase.

    fig. S9. CD spectra of the TSm phase.

    fig. S10. LC phase of straight rods with L/D < 3.5.

    fig. S11. LC phases of BRs with small α and L/D.

    fig. S12. LC phases of BRs with increased α and/or L/D.

    fig. S13. LC phase of BRs with large α but small L/D.

    fig. S14. LC phases of BRs with α ≥ 33° and L/D ≥ 8.0.

    fig. S15. LC phases of asymmetric BRs packed in an interdigitated arrangement.

    fig. S16. LC phases of asymmetric BRs packed in a loose arrangement fashion.

    fig. S17. Model of a BR.

    fig. S18. The order parameters of Formula and Formula vary with time for BR with α = 5° and L/D = 4.

    fig. S19. The order parameters of Formula and Formula vary with time for BR with α = 35° and L/D = 6.

    fig. S20. LC phases observed by simulations.

    table S1. Pressure components in three directions varying with Lz.

    note S1. Tensor order parameters.

    note S2. Orientation parameter.

    note S3. Uniaxial or biaxial order of BRs based on tensor order parameter.

    note S4. Twist or non-TSm phase of BRs based on both orientation and tensor order parameters.

    note S5. Simulation results.

    References (3537)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. SEM images of representative BRs with different geometries.
    • fig. S2. SEM images of representative asymmetric BRs with different geometries.
    • fig. S3. Sedimentation of BRs.
    • fig. S4. Volume fraction of BRs in the bottom ordered phase.
    • fig. S5. Flow feature of the LC phase.
    • fig. S6. Shear-induced LC formation.
    • fig. S7. POM images showing the long-range ordering of BRs in the SmCSPA phase.
    • fig. S8. Optical activity of the TSm phase.
    • fig. S9. CD spectra of the TSm phase.
    • fig. S10. LC phase of straight rods withL/D < 3.5.
    • fig. S11. LC phases of BRs with small α and L/D.
    • fig. S12. LC phases of BRs with increased α and/or L/D.
    • fig. S13. LC phase of BRs with large α but small L/D.
    • fig. S14. LC phases of BRs with α ≥ 33° and L/D ≥ 8.0.
    • fig. S15. LC phases of asymmetric BRs packed in an interdigitated arrangement.
    • fig. S16. LC phases of asymmetric BRs packed in a loose arrangement fashion.
    • fig. S17. Model of a BR.
    • fig. S18. The order parameters of Q002 and Q222 vary with time for BR with α = 5° and L/D = 4.
    • fig. S19. The order parameters of Q002 and Q222 vary with time for BR with α = 35° and L/D = 6.
    • fig. S20. LC phases observed by simulations.
    • table S1. Pressure components in three directions varying with Lz.
    • note S1. Tensor order parameters.
    • note S2. Orientation parameter.
    • note S3. Uniaxial or biaxial order of BRs based on tensor order parameter.
    • note S4. Twist or non-TSm phase of BRs based on both orientation and tensor order parameters.
    • note S5. Simulation results.
    • References (35–37)

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