ILCS

JungHyun Noh was born in Seoul, Korea. She obtained her B.Sc (2012) degrees from the College of Bionano Technology at Gachon University. Her research background during the undergraduate period was fabrication of superhydrophobic silica nanostructures based on Anodized Aluminum Oxide (AAO). Currently she started a combined master and doctorate program, and now she is a master student at the Graduate School of Convergence Science and Technology, Seoul National University. Under the guidance of Prof. Jan Lagerwall, her research topics focus on liquid crystal droplets and shells produced by capillary microfluidics.

Monidisperse droplets of chiral liquid crystal (consisting of the commercial multicomponent nematic mixture RO-TN 605 and the chiral dopant CB15) are produced in a coaxial nested glass capillary microfluidic device (following the design principle in Utada et al., MRS Bull., vol. 32, p. 702 (2007)). The droplets, with a diameter of 450µm, were suspended in an aqueous polyvinylalcohol (PVA) solution, inducing planar director alignment at the droplet surface and thus radial alignment of the cholesteric helix. For normal incidence this liquid crystal mixture reflects in the red, giving a red spot at the center of each droplet. We achieved a hexagonal 2D colloidal crystal arrangement of the droplets by collecting them at high volume fraction in a petri dish, giving rise to interesting patterns of green and yellow spots close to the droplet perimeter with strong six-fold and weak twelve-fold symmetry. These spots are apparently related to light being reflected between multiple droplets and eventually reflected (or scattered) upwards towards the camera, but the exact process has not yet been elucidated. The polarizing optical microscopic image has a background color due to the birefringent plastic of the petri-dish bottom plate.


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