• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.483-486
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• 2002

Tree-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent[1] were synthesized and their physical properties were measured to evaluate the applications to TFT-LCD TV. All synthesized compounds were showed remarkably high Tni point. Birefringence(${\triangle}n$) and dielectric anisotropy(${\triangle}{\varepsilon}$) were higher than fluoro analogues and isothiocyanate substituted bicyclohexyl-phenyl compounds.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1178-1178
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• 2004

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.277-282
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• 2003

Computational calculations are now successfully introduced to design liquid crystal molecules for uses in modern active-matrix displays. These material technologies are practically applied to develop novel compounds, enabling formulation of advanced liquid crystal mixtures together with a newly developed mixture purification method. Typical examples of these liquid crystal mixtures are introduced for modern displays in various applications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.571-574
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• 2003

Three ring type liquid crystalline compounds having 4-alklycyclohexyl group, 1,2-difluorobenzene and phenylisothiocyanate moieties as main skeleton were designed to have negative dielectricity. However, the compounds with 2,3,2'-trifluoro-3'-isothiocyanated biphenylcyclohexane core did not exhibit the nematic liquid crystalline phase because of two conformers by interaction of isothiocyanate and adjacent fluorine atoms. Also, 4-alkyl-2,2',3'-trifluoro-3-isothiocyanated biphenylcyclohexane core was designed expecting to have uniform conformers of isothiocyanate group. In the course of developing polyimides for VA mode LCD, we synthesized alkyl-3,5-diaminobenzene efficiently with various length of alkyl chains from commercially available di-t-butyl malonate and 3,5-dinitrobenzoyl chloride as starting material.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.471-474
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• 2002

Three-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent were synthesized and their physical and electro-optical properties were measured to evaluate the applications to active matrix VA liquid crystal displays. The tetrakis(triphenylphosphine)palladium(0) catalyzed cross coupling of aryl boronic acids with aryl halides is used to prepare trans-4'-Alkoxy-2,3-difluoro-3'-isothiocyanato-4-(4-alkylcyclohexyl}-biphenyl series. The synthesized compounds showed the nematic liquid crystalline phase and the negative dielectric anisotropy. The prepared mixtures showed faster response time and lower threshold voltage than their host mixture.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1142-1146
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• 2004

The synthetic route and physical properties for three-ring derivatives, trans-2,3,2',3'-tetrafluoro-4-alkyl-4'-(4-alkyl-cyclohexyl)-biphenyl and 4-alkyl-cyclohexane carboxylic acid 2,3,2',3',4'-pentafluoro-biphenyl-4-yl ester are presented. They exhibit broad range nematic phases exceeding 30K and low viscosity of nematic liquid crystal mixtures containing these materials. Their viscosity is compared with that of homologues with a lateral isothiocyanate group and show large negative dielectric anisotropies. The threshold voltage $V_{th}$ was low enough to be operated at a driving voltage of 5V. Our novel LC compounds are suitable materials for the improvement of dielectric anisotropy of vertical align liquid crystal displays (VA-LDCs).

• 한국기계연구소 소보
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• 통권13호
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• pp.15-25
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• 1984

The infrared spectra were determined to discover the characteristics and properties of poff-, PV-, and cc-samples, and studied influence on the formation of mesophase or liquid crystal. The experimental results were as follows; a) Samples with long aliphatic side chain appear cracking texture on temperature forming liquid crystal. b) The fine isotropic microstructure appears in a heterogeneous material containing sulfur, 7.18 w%. c) In the size of molecular weight the lighter than 500 form liquid crystal. d) When poff-sample was treated at $400^{\circ}C$ aliphatic hydrocabon compounds decrease, presented well-oriented bulk liquid crystal.

• 공업화학
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• 제9권1호
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• pp.66-70
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• 1998

정보전자 기기의 디스플레이용 재료로 사용되는 액정/고분자 복합재료의 매트릭스로 사용하기 위한 새로운 선형 및 가교형 측쇄 액정고분자를 제조하기 위하여 필요한 저분자 액정 중간체들을 합성하고 이들의 액정 특성을 살펴보았다. Alkyl spacer의 길이가 다르고 연결기로서 azo기를 그리고 말단기로서 cyano를 공통적으로 가지고 다른 한 말단기로서 bromoalkyl(AZO(n)), azidoalkyl(AZI(n)) 및 amonoalkyl(ALC(n))기를 가지는 저분자 액정 들의 합성을 하였으며 IR, NMR 및 원소분석을 통하여 이를 확인할 수 있었다. 또한 DSC thermogram 및 편광현미경 관찰로부터 이들 저분자 액정들은 모두 일정한 온도 영역에서 네마틱 상의 액정성을 발현하는 것을 알았다. 또한, 저분자 액정 분자들이 spacer 길이, 즉 $-(CH_2)n-$의 n이 짝수 및 홀수로 변화함에 따라 분자 내의 conformation 변화에 따른 $T_{KN}$과 $T_{NI}$의 값이 전형적인 even-odd 변화 현상을 나타내었다.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.69-74
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• 2017

본 연구에서는, 화합물의 액정 형성을 위한 메소젠기로써 콜레스테릴기를, 고체에서 액정상으로의 열 전이온도를 조절하기 위한 구조로써 알킬기를 포함하고 있는 콜레스테릭 액정 화합물인 콜레스테릴 4-n-알콕시벤조에이트 (Chol-n)를 합성하고, 이들 분자 내에 있는 알킬기의 탄소 사슬의 길이가 액정 화합물의 물성에 미치는 영향을 조사하였다. 합성된 액정화합물의 화학 구조와 열적 성질 및 액정성은 적외선 분광분석 (FT-IR), $^1H$-핵자기공명 분광분석 ($^1H$-NMR), 시차주사열량분석 (DSC) 그리고 편광현미경 (POM)을 이용하여 조사되었다. 연구 결과에 의하면, 합성된 화합물들의 용융 전이온도 ($T_m$)는 $103{\sim}143^{\circ}C$였고, 화합물 Chol-6을 제외한 모든 화합물들은 약 $60{\sim}100^{\circ}C$의 넓은 액정상 온도 구간을 나타냈으며, 분자내의 탄소 원자 수와 화합물의 열적 성질 사이의 상관성은 발견할 수 없었다. 합성된 모든 화합물들은 양방성 콜레스테릭 액정상을 보였고, 화합물 Chol-6, 8, 9, 및 10은 카이랄 스멕틱 액정상을 동반하였다. 그리고, 모든 화합물들은 액정 상태에서, 온도가 높아질수록 붉은 색 계통에서 푸른 색 계통으로 색이 변하는, 열 변색 현상을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.1939-1944
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• 2007

New liquid crystalline (biphenylcarbonyloxy)benzoates with an achiral swallow-tail derived from 3-alkoxy-2- (alkoxymethyl)-1-propanol [(ROCH2)2CHCH2OH, R = Me, Et, Pr, Bu] were prepared. These liquid crystals exhibited the phase sequence (I-SmA-SmCalt-(SmCX)-Cr) and showed antiferroelectric-like Smectic C phase (SmCalt) at temperature lower, and temperature range broader than do the compounds containing a branched alkyl group as a swallow-tail. The temperature ranges of antiferroelectric phase were found to be 30-90 oC and crystallization temperatures were 4-60 oC. The binary mixture of an achiral swallow-tailed liquid crystal and a chiral antiferroelectric liquid crystal, (S)-MHPOBC showed antiferroelectric smectic C phase at temperature much lower than the single chiral antiferroelectric liquid crystal does.