Characterization of surface anchoring energy of nematic liquid crystals via electrohydrodynamic instability

Dae Geon Ryu, Jong-Hoon Huh, Young-Ki Kim, and Jin Seog Gwag
Phys. Rev. E 101, 062703 – Published 18 June 2020

Abstract

Herein, a method is proposed to determine the azimuthal anchoring energies of surface liquid crystals (LCs), as they gradually change orientation from a vertical to a horizontal state owing to an increase in the voltage applied to each LC cell. The LC cells are characterized using the direction of the Williams roll pattern related to the midplane LC director of the conduction regime of the electrohydrodynamic convection patterns of LCs. The application of the midplane LC directions, obtained from the direction of the roll patterns, to the Ericksen-Leslie equation produces the precise values of the surface anchoring strength. The hybrid type 90°-twisted nematic LC cell, composed of homeotropic and homogeneous LC alignment layers on the top and bottom substrates, respectively, was used to find the azimuthal anchoring energy of the surface LCs, indicated by voltages at the initially vertically aligned LC state. It was observed that the surface azimuthal anchoring energy on the homeotropic layer increased with an increase in voltage. We expect that the proposed technique may be excellent in terms of ease of use, simplicity, and accuracy because the azimuthal anchoring energy can be visually evaluated through the roll pattern.

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  • Received 22 January 2020
  • Revised 25 May 2020
  • Accepted 27 May 2020

DOI:https://doi.org/10.1103/PhysRevE.101.062703

©2020 American Physical Society

Physics Subject Headings (PhySH)

Polymers & Soft MatterFluid Dynamics

Authors & Affiliations

Dae Geon Ryu1, Jong-Hoon Huh2, Young-Ki Kim3,*, and Jin Seog Gwag1,†

  • 1Department of Physics, Yeungnam University, 280 Daehak-Ro, Gyeongsan 38541, Republic of Korea
  • 2Department of Mechanical Information Science and Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka 820–8502, Japan
  • 3Department of Chemical Engineering, Pohang University of Science and Technology, 67 Cheongam-ro, Pohang, Gyeongbuk 37673, Republic of Korea

  • *Corresponding author: ykkim@postech.ac.kr
  • Corresponding author: sweat3000@ynu.ac.kr

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Issue

Vol. 101, Iss. 6 — June 2020

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