• Title/Summary/Keyword: Y-shaped mesogens

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Synthesis and Properties of Polyesters with Bent-Shaped Mesogens Containing Naphthalene Central Unit

  • Seo, Young-Ho;Choi, E-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.633-636
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    • 2009
  • New polyesters with bent-shaped mesogens were synthesized varying the central unit with 1,6- and 2,3- naphthylenes, and introducing the dodecamethylene flexible spacer. The mesogenic properties of the polymers were characterized by FT-IR spectroscopy, DSC, polarizing optical microscopy.

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Synthesis and characterization of Reactive Banana-Shaped Mesogens

  • Choi, Min-Ho;Choi, E-Joon;Kim, Young-Chul;Park, Sang-Hyon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.854-857
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    • 2006
  • The synthesis of ester type, banana-shaped, photo - crosslinkable mesogens is described. The reactive mesogens, derivatives of 1,3-phenylene bis{4-[4'- (alken-1-yloxy)-biphenyl-4-carboxylate]benzoate}s, were synthesized varying the length of alkyl end groups. The obtained monomers and polymers were characterized by FT/IR, NMR spectroscopy, DSC, polarized optical microscopy, and X-ray diffractometry.

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Synthesis and Properties of Liquid Crystalline Y-shaped Molecules Containing 1,3,4-Oxadiazole

  • Kwon, Eun-Kyoung;Choi, E-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.542-544
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    • 2007
  • New liquid crystalline Y-shaped molecules containing 1,3,4-oxadizoles have been synthesized with variation of terminal groups (R = H, $OCH_3$ or $OC_8H_{17}$). The structures of obtained compounds were identified by FT/IR and NMR spectrometry, and their thermal and liquid crystalline properties were investigated by DSC and polarizing optical microscope.

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Synthesis and Biaxial Nematic Properties of Novel Liquid Crystalline X-shaped Mesogens Containing Perfluoroalkyl Alkanes as a Side Chain

  • Lee, Byung-Hoon;Choi, E-Joon;Park, Sang-Byung;Zin, Wang-Choel;Lee, Gak-Seok;Yoon, Tae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.324-326
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    • 2008
  • Novel X-shaped molecules containing perfluoroalkyl alkanes as a side chain have been synthesized and characterized. The properties of mesophases were investigated by a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), X-ray diffractometry (XRD) and electro-optical measurements.

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Synthesis and Properties of Liquid Crystalline Polyesters with Banana-Shaped Mesogens

  • Kwon, Myeong-Hoon;Kim, Sea-Yun;Choi, E-Joon;Lee, Jong-Chan;Zin, Wang-Cheol;Lee, Chong-Kwang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1223-1224
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    • 2004
  • A series of LC polyesters containing banana-shaped mesogen and flexible spacer were synthesized. Their structures were identified by FT/IR- and NMR-spectrometry. Thermal and mesomorphic properties were investigated by using DSC and polarizing microsope. Structure of mesophase was investigated by using x-ray diffractimetry.

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Chiral Mesophase Derived from Achiral Polymers with Banana-Shaped Mesogens and Their Model Compounds

  • Choi, E-Joon;Kim, Eun-Chul;Kwon, Myung-Hun;Zin, Wang-Cheol;Kim, Young-Chul;Paek, Sang-Hyon
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.242-243
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    • 2006
  • In this work, we report the synthesis and characterization of azomethineester polymers that consist of banana-shaped mesogen in their backbone. Two parts of the key structure of five-ring bent-core mesogen were modified by connecting different angle of central unit (Ar), and introducing lateral substituent into the outer ring (X). The synthetic details includes (1) placing the dioxydodecamethylene unit as a flexible spacer, (2) possessing 2,3- or 2,7-naphthylene, or 1,2-phenylene connection on the central unit, and (3) introducing fluorine or chlorine substituent (X = F or Cl) into the outer phenylene unit.

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Synthesis and Mesomorphism of Polymers with Banana-Shaped Mesogens in the Main Chain

  • Choi, E-Joon;Zin, Wang-Cheol;Kim, Young-Chul;Paek, Sang-Hyon;Chien, Liang-Chy;Samulski, Edward T.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.171-174
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    • 2006
  • In this work, we report the synthesis and characterization of azomethine-ester polymers that consist of banana-shaped mesogen in their backbone. Two parts of the key structure of five-ring bent-core mesogen were modified by connecting different angle of central unit (Ar), and introducing lateral substituent into the outer ring (X). The synthetic details includes (1) placing the dioxydodecamethylene unit as a flexible spacer, (2) possessing 2,3- or 2,7-naphthylene, or 1,2-phenylene connection on the central unit, and (3) introducing fluorine or chlorine substituent (X = F or Cl) into the outer phenylene unit.

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Synthesis and Properties of Biaxial LC from Dumbbell-shaped Molecules

  • Xu, Fei;Choi, E-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.651-654
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    • 2009
  • Novel compounds with rod and disc mesogens were synthesized and characterized. The molecular structures were confirmed by FT-IR, $^1H$-NMR spectroscopy and elemental analysis. The optical properties of these molecules were investigated by UV-vis absorption spectroscopy and photo-luminescence spectroscopy. We found that they are a novel series of blue light-emitting molecules. The absorption spectra peaks of these compounds varied from 336 nm-341 nm, while the maximum emissions centered form 410 nm-450 nm in chloroform solution. However, unexpectedly we could not found their biaxiality and mesomorphic properties by POM, conoscopy and DSC method.

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Synthesis and Mesomorphic Properties of Banana-Shaped Mesogens with All-Ester Linking Group

  • Choi, E-Joon;Cui, Xin;Zin, Wang-Choel;Ohk, Chang-Woo;Lim, Tong-Kun;Lee, Ji-Hoon;Kim, Young-Chul;Paek, Sang-Hyon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.197-199
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    • 2007
  • Four banana-shaped compounds have beene synthesized introducing ester linking group into mesogenic unit, varying the central core with 1,6-, 1,7-, 2,3-, and 2,7-naphthylene units, and introducing the dodecyloxy group as the terminal flexible unit. All obtained compounds except one with 1,7-naphthylene unit were reversibly thermotropically liquid crystalline. The compound with 1,7-naphthylene unit could not form the mesophase due to its asymmetrical and sharp substitution angle. The compounds with 1,6- and 2,3-naphthylene units showed an antiferroelectric switchable smectic phase, which has been designated B2 phase. Interestingly, the compound with the 2,3-naphthylene unit showed the two mesophases of B2 and nematic phase.

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