Spontaneous and diverse morphological transitions of nematic liquid crystal oligomer micro-droplets

ORAL

Abstract

Viruses and pollen grains are known for their diverse morphologies and surface patterns, which play important roles to their functions. It begs the questions how the patterns were originated and then evolved. Here, we report the spontaneous morphological transformations from micro-droplets, consisting of polydispersed nematic liquid crystal oligomers (NLCOs) suspended in water, to a strikingly rich set of nematic structures, including roughened spheres, flowers, and filamentous structures. We investigate the interplay of elasticity and interfacial tension within the drop as a function of temperature, surfactant concentrations, and the LCO chain length distribution. We show that heterogeneity of LCO chain length is a feature leading to segregation of LCOs within the micro-droplet. The transformed morphologies are highly uniform in size and can be locked via UV curing. The study of synthetic systems offers a first attempt to understand the origin of complex morphologies in biological world.

*This work is supported by NSF DMR16-07378, PENN MRSEC Grant DMR-1720530, and NASA Grant NNX08AO0G.

–

Presenters

  • Wei-Shao Wei

    • Department of Physics and Astronomy & LRSM, University of Pennsylvania, Philadelphia, PA, USA

Authors

  • Wei-Shao Wei

    • Department of Physics and Astronomy & LRSM, University of Pennsylvania, Philadelphia, PA, USA

  • Yu Xia

    • Department of Materials Science and Engineering, University of Pennsylvania
    • Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA
    • Chemical and Biological Engineering, Princeton University

  • Sophie Ettinger

    • Department of Physics and Astronomy & LRSM, University of Pennsylvania, Philadelphia, PA, USA
    • Physics and Astronomy, University of Pennsylvania

  • Shu Yang

    • Department of Materials Science and Engineering, University of Pennsylvania
    • Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA
    • University of Pennsylvania

  • A. G. Yodh

    • Department of Physics and Astronomy & LRSM, University of Pennsylvania, Philadelphia, PA, USA
    • Department of Physics and Astronomy, University of Pennsylvania
    • University of Pennsylvania