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Proceedings Paper

Dielectrophoretic manipulation of nematic and isotropic droplets
Author(s): Bomi Lee; Jang-Kun Song
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Paper Abstract

Dielectrophoresis can provide a delicate tool to control electrically neutral particles in colloid. The dielectrophoresis is usually applied to solid particles or heterogeneous liquid droplet in continuous liquid, but we devised and investigated the dielectrophoresis of isotropic droplets within nematic phase or vice versa. Using multi-components liquid crystal mixtures that exhibit relatively wide temperature range of nematic-isotropic coexistence, we achieved a field-induced phase separation between isotropic and nematic. We also fabricated the isotropic-nematic filaments that was achieved using a biased surface preference for either isotropic or nematic phase of the alignment layer [1]. The dielectrophoresis manipulations of isotropic and nematic droplets required much lower voltage compared to that for the electro wetting type devices. In addition, we observed the bi-directional actuation of isotropic droplets using anisotropic dielectric property of liquid crystal, which is not possible in usual dielectrophoresis. The bidirectional actuation was achieved by controlling the LC director within the cell so as to change the sign of the difference between the effective dielectric constant of nematic and isotropic liquid crystals. We simulated the bi-directional dielectrophoresis by performing the LC director calculation and the corresponding dielectrophoresis. The simulation results matched well with the experimental data. Thus, the bi-directional dielectrophoresis using isotropic and nematic droplets may open new possibility of electro- optical applications using liquid crystals.

Paper Details

Date Published: 7 March 2016
PDF: 6 pages
Proc. SPIE 9769, Emerging Liquid Crystal Technologies XI, 976919 (7 March 2016); doi: 10.1117/12.2231146
Show Author Affiliations
Bomi Lee, Sungkyunkwan Univ. (Korea, Republic of)
Jang-Kun Song, Sungkyunkwan Univ. (Korea, Republic of)

Published in SPIE Proceedings Vol. 9769:
Emerging Liquid Crystal Technologies XI
Liang-Chy Chien; Dick J. Broer; Hirotsugu Kikuchi; Nelson V. Tabiryan, Editor(s)

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