• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.571-574
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• 2005

We demonstrated a high speed liquid crystal (LC) display mode based on a nonchiral smectic C LC in an antiparallel planar geometry. In this antiparallel planar nonchiral smectic C (APNSC) LC mode, analog gray scales and wide viewing properties are achieved using a stepwise thermal annealing process (STAP). Because of an initially stable LC alignment in large area through the STAP, the APNSC LC mode exhibits the characteristics of fast response and high contrast ratio. This new APNSC mode is suitable for processing the dynamic image at a video rate in the next-generation LCDs.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.567-570
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• 2003

We demonstrated a fast liquid crystal (LC) display mode based on a nonchiral smectic C LC in a twisted geometry. In this twisted nonchiral smectic C (TNSC) LC mode, the analog gray scales and wide viewing properties are achieved. The continuous gray scales in the TNSC LC mode are obtained in a dielectrically driving scheme as those in the nematic mode.

• Macromolecular Research
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• v.17 no.5
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• pp.313-318
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• 2009

The side chain liquid crystal triblock copolymers (TBCs), which underwent phase transitions below their decomposition temperature, were prepared by copolymerization of poly(n-butyl acrylate) and a comonomer containing the mesogenic azobenzene group. The physical properties of TBCs in the distinctive transition temperature ranges were investigated in terms of the liquid crystal (LC) content in the copolymers. The phase transition temperatures traced optically, thermally and rheologically were well coincided one another and clearly exhibited the phase transition of smectic-nematic-isotropic with increasing temperature. In the smectic phase, increasing temperature made the liquid crystal system more elastic, but viscosity (${\eta}'$) remained almost constant. In the nematic phase, increasing temperature abruptly decreased ${\eta}'$ and G', ultimately leading to isotropic phase. Both smectic and nematic phases exhibited Bingham viscosity behavior but the former gave much greater yield stress at the same LC content.

• Journal of Information Display
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• v.6 no.3
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• pp.6-11
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• 2005

In this paper, a general performance of the PSS-LCD or Polarization Shielded Smectic Liquid Crystal Display is discussed. This smectic base LCD does not use any spontaneous polarization, but uses induced polarization just sa me with current nematic base LCDs. Specific initial molecular alignment as well as specific cell design realizes ext remely fast optical response speed with native wide viewing angle. Moreover, this performance is provided by full compatible electronics for current conventional LCDs. A general performance of the PSS-LCD is introduced herein.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.467-470
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• 2002

We report on an analog electro-optic effect in a nonchiral smectic C (NSC) liquid crystal (LC) mode with negative dielectric anisotropy in a transverse electrode configuration. Two-dimensional numerical simulations are executed to evaluate the display performances. The analog gray scales in the NSC LC mode are obtained in a dielectrically driving scheme.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1389-1392
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• 2009

A series of new symmetric TTF derivatives were designed and synthesized. This facile synthetic method provides an opportunity to prepare TTF-based LC candidates. This series of compounds exhibited smectic A phase based on coplanar TTF core. One of the LC compounds was used as a semiconductor layer to fabricate OTFT.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1651-1655
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• 2007

Rod-like polymerizable LC molecules having two different reactive groups, i.e. acryl and diacetylene groups were prepared. 4-Hydroxyphenyldiacetylenes were synthesized by the coupling reaction of 1-bromoalkynes with 4-ethynylphenol and then reacted with 4-(6-acryloyloxyalkyloxy)benzoic acid to give polymerizable LC molecules 4a-d. The mesomorphic properties of compounds 4a-d were investigated by differential scanning calorimetry, polarized optical microscopy and X-ray diffractometry. Compounds 4a-c exhibited smectic and nematic phases, but compound 4d having a longest alkyl tail among the series formed only a smectic phase. Photopolymerizability of acryl and diacetylene groups was investigated by IR spectroscopy. An anisotropic polymer film could be prepared by selective polymerization of acryl groups with 365 nm UV light in the presence of a photoinitiator (2,2-dimethoxy-2-phenylacetophenone). The subsequent reaction of diacetylene groups with 254 nm UV light disrupted the anisotropic structure, suggesting that these LC molecules could be used for imaging on the film.

• Composites Research
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• v.30 no.6
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• pp.350-355
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• 2017

The new liquid crystalline (LC) epoxy was designed by substituting the phenylcyclohexyl (PCH) mesogen moiety with an alkyl chain at the 2,5 position of the diglycidyl terephthalate. The mesomorphic properties were evaluated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). All LC epoxy derivatives exhibited an enantiotropic smectic phase upon heating and cooling process. The LC phase temperature range was widened by mixing the eutectic mixture of LC epoxies. Interestingly, the cured LC epoxy exhibited the highest thermal conductivity of $0.4W{\cdot}m^{-1}{\cdot}K^{-1}$. The novel LC epoxy with high thermal conductivity might be used as a composite material for electronic and display devices.

• Polymer(Korea)
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• v.34 no.4
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• pp.369-375
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• 2010

We used melt polymerization method to prepare a series of aromatic liquid crystals (LCs) based on aromatic ester and amide units with the reactive methyl-maleimide end group, and then the resulting thermally cross-linked LCs to produce LC thermoset films by means of solution casting and the followed heat treatment. The synthesized LCs and LCTs were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), X-ray diffractometry (XRD), and polarizing optical microscopy (POM) with a hot stage. All of the LCs prepared by melt polymerization method formed smectic mesophases. The thermal properties of the LC and LCT films were strongly affected by the mesogen units in the main chain structures. The thermal expansion coefficients of samples were in the range of 27.72~50.95 ppm/$^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.725-727
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• 2011