한국정보전자통신기술학회논문지 (The Journal of Korea Institute of Information, Electronics, and Communication Technology)

  • 제11권6호
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  • Pages.671-677
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  • 2018
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  • 2005-081X(pISSN)
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  • 2288-9302(eISSN)
한국정보전자통신기술학회 (Korea Information Electronic Communication Technology)
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Liquid crystal alignment on rubbed self-assembled monolayers with fluorinated alkyl chain

  • Oh, Chan-Woo (School of Electrical, Electronic and Control Engineering, Changwon National University) ;
  • Hwang, Seok-Gon (School of Electrical, Electronic and Control Engineering, Changwon National University) ;
  • Park, Sang-Geon (Division of Smart Electrical and Electronic Engineering, Silla University) ;
  • Park, Hong-Gyu (School of Electrical, Electronic and Control Engineering, Changwon National University)
  • 투고 : 2018.11.05
  • 심사 : 2018.11.21
  • 발행 : 2018.12.29
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초록

In this paper, we investigated the vertical alignment characteristics of liquid crystals (LCs) on fluorinated self-assembled monolayers (FSAMs). For comparison, a commercialized homeotropic polyimide (PI) layer was used as an LC alignment layer. We confirmed the successful deposition of FSAMs and the change of FSAMs before and after rubbing treatment through contact angle measurement and atomic force microscopy. The optical transmittance spectrum of the FSAMs is similar to that of the homeotropic PI layer, which is a superior optical characteristic applicable to LC devices. When FSAMs were applied to the vertically aligned (VA) LC cell, uniform and vertical LC alignments were achieved. In addition, the voltage-transmittance characteristic of VA LC cell with FSAMs was superior to that of VA LC cell with the conventional homeotropic PI layers. These results indicate that the FSAMs are suitable as the homeotropic LC alignment layer for enhanced LC devices.

키워드

JBJTBH_2018_v11n6_671_f0001.png 이미지

Fig. 1. Contact angles of the homeotropic PI layers and FSAMs before and after rubbing treatment: (a-b) homeotropic PI and (c-d) FSAM.

JBJTBH_2018_v11n6_671_f0002.png 이미지

Fig. 2. AFM images of the homeotropic PI layers and FSAMs before and after rubbing treatment: (a-b) homeotropic PI and (c-d) FSAM.

JBJTBH_2018_v11n6_671_f0003.png 이미지

Fig. 3. Optical transmittance spectra of the LC cells with the homeotropic PI layers and FSAMs.

JBJTBH_2018_v11n6_671_f0004.png 이미지

Fig. 4. LC orientations and pretilt angles: Photomicrographs of LC cells with (a) the homeotropic PI layer and (b) FSAMs (A: analyzer; P: polarizer) and the rotational transmittance curves obtained from the pretilt angle measurement (blue curve: simulated curve; red curve: experimental curve).

JBJTBH_2018_v11n6_671_f0005.png 이미지

Fig. 5. Voltage-transmittance curve of VA LC cells with the homeotropic PI layers and FSAMs.

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