Direct observation of lens-shaped nematic tactoids and micro-phase separation in aqueous suspensions of $\alpha $-zirconium phosphate nanosheets

ORAL

Abstract

We study the ordering of monolayer $\alpha $-zirconium phosphate nanosheets in aqueous suspensions. As the concentration increases, we confirm that the inter-plate spacing decreases, the X-ray correlation increases, and there is nematic ordering even at the highest concentrations. The inter-plate spacing shows linear swelling behavior, but not as expected for a uniform swelled system. The micro-phase separation is proposed and further demonstration by centrifugation, optical microscope, confocal fluorescent microscope and freeze fracture TEM. Self-assembling of stacks of the platelets are proposed to form liquid crystal phases. Lens-shaped tacoids with radial director field are observed, and the quantitative analysis of the tactoid properties gives estimates of ratios of the bulk elastic constant, anchoring strength to the bare surface tension.

*This work was supported by NSF MRSEC Grant DMR-0820579 and NSF Grant DMR-1006870.

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Authors

  • Yue Shi

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA

  • Min Shuai

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA

  • Yongqiang Shen

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA

  • Dong Chen

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA

  • Joseph Maclennan

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA

  • Zhengdong Cheng

    • McFerrin Department of Chemical Engineering, Texas A\&M University, College Station, TX 77843, USA

  • Noel Clark

    • Department of Physics, Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA