• Title/Summary/Keyword: Liquid Crystalline

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Microstructural Morphology of Molded Thin Composites of Thermotropic Liquid Crystalline Polymer and Polyamide 6 (서모트로픽 액정폴리머와 폴리아미드6으로 성형된 얇은 복합재료의 미세구조형태)

  • Choe, Nak-Sam;Choe, Gi-Yeong;Ha, Seong-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.7 s.178
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    • pp.1703-1711
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    • 2000
  • Microstructural morphology of molded composites of thermotropic liquid crystalline polymer(LCP) and polyamide 6 (PA6) has been studied as a function of epoxy fraction. Injection-moulding of a thin composite plaque at a temperature below the melting point of the LCP fibrils by suing the extruded LCP/PA6 pellets produced multi-layered structures: 1) the surface skin layer with thickness of 65-120 ym exhibiting a transverse orientation, 2) the sub-skin layer with an orientation perpendicular to the surface skin, i.e. in the flow direction, 3) the core layer with arc-curved flow patterns. Similar microstructural orientations were observed in the respective layers for the composite plaques with different fractions of epoxy.

Research of Thermal Properties for Liquid Crystalline Epoxy Composites with Tin Oxide Filler (산화주석을 함유한 열경화성 액정 에폭시의 열적 특성에 관한 연구)

  • Hyun, Ha Nuel;Cho, Seung Hyun
    • Composites Research
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    • v.33 no.1
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    • pp.25-29
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    • 2020
  • A liquid crystalline thermosetting-epoxy-based composite was fabricated using diglycidyl ether of 4,4'-biphenol, tin(IV) oxide as a filler, and sulfanilamide as a curing agent. To investigate the thermal behavior, Thermogravimetric Analysis and Laser Flash Apparatus were performed using 3.0-7.0 wt% Tin(IV) oxide. The result showed that the activation energy and thermal conductivity were proportional to the amount of added filler.

Liquid Chromatography-Solid Phase Extraction-NMR (LC-SPE-NMR) Analysis of Liquid Crystalline Mixtures

  • Park, Gregory Hyung-Jin;Park, Ae-Na;Rho, Kyung-Rae;Shin, Jong-Ho;Kim, Yeong-Jeon;Jo, Sung-Chan;Oh, Weon-Sik
    • Journal of the Korean Magnetic Resonance Society
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    • v.15 no.1
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    • pp.14-24
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    • 2011
  • We have performed Liquid Chromatography-Solid Phase Extraction-NMR (LC-SPE-NMR) analysis for liquid crystalline mixture and elucidated the structures of selected components by NMR spectra. Combining the results of one-dimensional 1H experiments as well as homonuclear and heteronuclear two-dimensional experiments, we could analyze the molecular structure of the liquid crystal singles whose structure had not been interpretable by mass spectrometry alone.

Synthesis of Three Ring Type Compounds with Fluorine and NCS Groups as Candidates for VA mode Liquid Crystal Display

  • Heo, E.Y.;Kim, Y.B.;Kim, S.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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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.

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Novel Liquid Crystal Compounds and Its Mixtures for VA-TFT-LCD TV Application

  • Kim, Y.B.;Roh, S.D.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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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.

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Bending and Pressing Tolerance of Flexible Polyoxetane based Liquid Crystalline Polymer/Low Molecular Weight Liquid Crystal Device

  • Jang, Chi-Woong;Lim, Tong-Kun;Kim, Moo-Jong;Kim, Ku-Nam;Kwon, Young-Wan;Jin, Jung-Il;Bae, Jung-Hun;Kim, Han-Sik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.433-435
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    • 2005
  • We have studied the realigning behavior of liquid crystal molecules in liquid crystalline polymer/liquid crystal(LCP/LC) system when they are exposed to external stimulation such as bending and pressing. The birefringence of the LCP/LC in a flexible display device was measured as a function of bending or pressing deformation. The microscopic dynamic behavior of main chain, side chain, and the LC were characterized by FTIR and polarization optical microscopy. When the device is deformed in scattering memory state, liquid crystal(LC) director is found to align from randomly oriented domain state(scattering state) to homeotropic state.

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Morphology Control of Single Crystalline Rutile TiO2 Nanowires

  • Park, Yi-Seul;Lee, Jin-Seok
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3571-3574
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    • 2011
  • Nano-scaled metal oxides have been attractive materials for sensors, photocatalysis, and dye-sensitization for solar cells. We report the controlled synthesis and characterization of single crystalline $TiO_2$ nanowires via a catalyst-assisted vapor-liquid-solid (VLS) and vapor-solid (VS) growth mechanism during TiO powder evaporation. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies show that as grown $TiO_2$ materials are one-dimensional (1D) nano-structures with a single crystalline rutile phase. Also, energy-dispersive X-ray (EDX) spectroscopy indicates the presence of both Ti and O with a Ti/O atomic ratio of 1 to 2. Various morphologies of single crystalline $TiO_2$ nano-structures are realized by controlling the growth temperature and flow rate of carrier gas. Large amount of reactant evaporated at high temperature and high flow rate is crucial to the morphology change of $TiO_2$ nanowire.

Blends of Silicone Rubber and Liquid Crystalline Polymer

  • Shivakumar E.;Das C. K.;Pandey K. N.;Alam S.;N.Mathur G.
    • Macromolecular Research
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    • v.13 no.2
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    • pp.81-87
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    • 2005
  • Blends of silicone rubber (VMQ) and liquid crystalline polymer (LCP) were prepared by the melt mixing technique. Mechanical, XRD, thermal and dynamic mechanical investigations are reported for the pure silicone rubber and blends. The mechanical properties, viz. the tensile strength, tear strength and elongation at break, of the silicone rubber decreased with the addition of LCP. The SEM study on the tensile fractured surface of the blends revealed that they had a two phase structure, and that the failure was mainly due to fiber pull out, which suggests that the VMQ and LCP are incompatible in all of the proportions examined in this study. However, the FTIR study shows that there was a partial interaction between the VMQ and LCP, but which may not be sufficient to grip the fibrils under the applied load. In the XRD analysis, it was observed that the crystalline structure of the silicone rubber deteriorated in the presence of LCP. The DMA study suggested that the storage modulus of the silicone rubber was improved with the addition of LCP, due to the high modulus of the LCP phase. The thermal stability of the silicone rubber was greatly reduced by the addition of LCP, due to the latter having a thermal stability lower than that of silicone rubber.

Fabrication of the Outer type-Dynamic Microlens Array using Surface-Stabilized Ferroelectric Liquid Crystal

  • Kim, Young-Wook;Gwag, Jin-Seog;Kim, Kyung-Bae;Kang, Tae-Ho;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.344-347
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    • 2008
  • We fabricated the outer type-dynamic microlens array using a surface-stabilized ferroelectric liquid crystal, UV curable polymer and the stacked liquid crystalline polymer. The outer type-microlens array has a lower driving voltage and fast switching property. It is applicable to a variety of optical systems.

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