Research ArticlePHYSICS

Nanoparticle-laden droplets of liquid crystals: Interactive morphogenesis and dynamic assembly

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Science Advances  05 Jul 2019:
Vol. 5, no. 7, eaav1035
DOI: 10.1126/sciadv.aav1035
  • Fig. 1 NP-free Ch-CNC droplets.

    3D (A) and cross-sectional schematics (B and D) and corresponding POM images (C and E) of the Ch-CNC droplets, with the OO′ and HH′ axes perpendicular to the z axis (B and C) and the HH′ axis parallel to the z axis (D and E). The light gray rings and dark blue rods in (A) represent the Ch-CNC pseudolayers and the CNCs, respectively. The dashed and dotted lines in (B) and (D) represent the CNC pseudolayers. In (C) and (E), φ0 = 4.3 × 10−2. Scale bars, 10 μm.

  • Fig. 2 Self-assembly of NPs in the Ch-CNC droplets.

    Schematics of the composite latex NP/Ch-CNC droplets with BP (A), TR (F), and core-shell disclination (CSD) (K) assemblies of the NPs. Representative fluorescence microscopy (B, G, and L), POM (C, H, and M), and merged (D, I, and N) images of the same NP/Ch-CNC droplet. (E, J, and O) 3D confocal fluorescence microscopy images of the NP assemblies with BP (E), TR (J), and CSD (O) structure. φNP is 5.5 × 10−4 in (B) to (E) and 1.1 × 10−3 in (G) to (O). φ0 = 4.3 × 10−2. Ch pseudolayers form flat-ellipsoidal structures in (A) to (J). Scale bars, 10 μm. Left: Orientation of the OO′ and HH′ axes (as in Fig. 1) and the corresponding notations for the orientation of the OO′ and HH′ axes with respect to the z axis (the optical axis of the microscope). The dashed and dotted lines and green deposits represent the CNC pseudolayers and latex NPs, respectively.

  • Fig. 3 Analysis of droplet morphologies.

    (A) Distribution of the populations of droplets with BP, TR, and CSD assemblies of NPs. For each sample, at least, 300 droplets were analyzed. φ0 = 4.3 × 10−2 in all the samples. (B) State diagram of the morphologies of NPs in the Ch-CNC droplets.

  • Fig. 4 Morphogenesis in the Ch-CNC host droplets and NP assemblies.

    (A) Flat-ellipsoidal/BP. (B) Flat-ellipsoidal/TR. (C) Core-shell/CSD. Gray planes represent the Ch-CNC pseudolayers. Green color marks latex NP assemblies. Labels above each schematic show the corresponding Ch-CNC packing mode (red font) and the NP assembly mode (blue font). To illustrate NP assembly, the schematics does not show the continuous twist of the CNCs.

  • Fig. 5 Interactive morphogenesis in Ch-CNC droplets laden with magnetic NPs.

    Representative schematic (A to C) and corresponding bright-field (A′, B′, and C′) and POM (A″, B″, and C″) images of the Ch-CNC droplets loaded with Fe3O4 NPs with TR (A′, A and B′, B) and CSD (C′ and C) assemblies. φNP = 9.7 × 10−4 and 1.9 × 10−3 in (A′ to B) and in (C′) and (C), respectively. No magnetic field is applied. Representative schematic (D and E) and corresponding bright-field (D′ and E′) and POM (D″ and E″) images of the Ch-CNC droplets loaded with Fe3O4 NPs at φNP = 9.7 × 10−4 and exposed to a 0.35-T magnet for 3 days. φ0 = 4.3 × 10−2 in all the samples. Scale bars, 10 μm. Top row shows the orientation of the OO′ and HH′ axes (as in Fig. 1) and the corresponding notations for the orientation of the OO′ and HH′ axes with respect to the z axis (the optical axis of the microscope). Dashed lines and dotted lines and green deposits represent the CNC pseudolayers and NPs, respectively. (F) Z-stack fluorescence microscopy images of the Ch-CNC droplets shown in (D) and (E). The 0-μm position corresponds to the central plane of the droplets, and the images were taken on the top (negative values) to the bottom (positive values) of this plane. φNP = 9.7 × 10−4 and φ0 = 4.3 × 10−2 in all the samples. Scale bars, 10 μm.

  • Fig. 6 Different models of assembly of Ch-CNC droplets laden with Fe3O4NPs under magnetic field.

    (A to C) Schematic and corresponding bright-field (B) and POM (C) images of chains formed by Ch-CNC droplets with BP and TR assemblies of NPs. Droplets with the CSD assembly of NPs showed similar assembly in linear chains and are not shown. (D to F) Schematic and corresponding bright-field (E) and POM (F) images of staggered chains formed by Ch-CNC droplets loaded with magnetic NPs that were localized in the subsurface layer on one side of the droplets. φNP = 9.7 × 10−4 and φ0 = 4.3 × 10−2. Scale bars, 20 μm. HH′ axis was parallel to the z axis in (C and F).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/7/eaav1035/DC1

    Fig. S1. TEM characterization of CNCs and latex NPs.

    Fig. S2. Optical microscopy images of the Ch-CNC/NP droplets generated in the MF flow-focusing droplet generator.

    Fig. S3. Characterization of the Ch-CNC droplets loaded with latex NPs.

    Fig. S4. Characterization of the NP-free Ch-CNC droplets.

    Fig. S5. Phase separation of mixtures of Ch-CNC suspension and latex NPs.

    Fig. S6. Schematic of the flat-ellipsoidal droplet structure of the Ch-CNC droplets.

    Fig. S7. TEM images of magnetic Fe3O4 NPs.

    Fig. S8. Characterization of the Ch-CNC droplets loaded with magnetic NPs.

    Fig. S9. 3D assemblies of the Ch-CNC droplets loaded with Fe3O4 NPs.

    Fig. S10. Characterization of the Ch-CNC droplets with the layers of magnetic NP.

    Fig. S11. Two models of assembly of the Ch-CNC droplets laden with Fe3O4 NPs under the magnetic field.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. TEM characterization of CNCs and latex NPs.
    • Fig. S2. Optical microscopy images of the Ch-CNC/NP droplets generated in the MF flow-focusing droplet generator.
    • Fig. S3. Characterization of the Ch-CNC droplets loaded with latex NPs.
    • Fig. S4. Characterization of the NP-free Ch-CNC droplets.
    • Fig. S5. Phase separation of mixtures of Ch-CNC suspension and latex NPs.
    • Fig. S6. Schematic of the flat-ellipsoidal droplet structure of the Ch-CNC droplets.
    • Fig. S7. TEM images of magnetic Fe3O4 NPs.
    • Fig. S8. Characterization of the Ch-CNC droplets loaded with magnetic NPs.
    • Fig. S9. 3D assemblies of the Ch-CNC droplets loaded with Fe3O4 NPs.
    • Fig. S10. Characterization of the Ch-CNC droplets with the layers of magnetic NP.
    • Fig. S11. Two models of assembly of the Ch-CNC droplets laden with Fe3O4 NPs under the magnetic field.

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