• 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.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.5-9
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• 2003

The liquid crystal (LC) aligning capabilities by the washing processes after rubbing on the two kinds of the rubbed polyimide (Pl) surface were studied. The polar anchoring energy of 4-n-pentyl-4'-cyanobiphenyl (5CB) increased with the rubbing strength RS on the two kinds of the rubbed PI surface. The polar anchoring energy of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Also, the surface ordering of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Therefore, the surface ordering of 5CB strongly depends on the polymers and washing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.506-509
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• 2003

The liquid crystal (LC) aligning capabilities by the washing processes after rubbing on the two kinds of the rubbed polyimide (PI) surface were studied. The polar anchoring energy of 4-n-pentyl-4'-cyanobiphenyl (5CB) increased with the rubbing strength RS on the two kinds of the rubbed PI surface. The polar anchoring energy of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Also, the surface ordering of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Therefore, the surface ordering of 5CB strongly depends on the polymers and washing process.

• Polymer(Korea)
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• v.29 no.6
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• pp.523-535
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• 2005

Linear aromatic polyesters are representative examples of thermotropic liquid crystalline polymers (TLCPs), which have been the subject of many researches. This article reviews the structure-LC properties relationship in wholly aromatic CLCPs mostly based on the results obtained for the past quarter of a century. Especially, this review deals with the structural details of aromatic polyester TLCPs that influence the liquid crystalline and thermal properties. In the last part of this article the liquid crystalline properties of combined type and hyperbranched polyester also are discussed. Introduction to various synthetic methods are included in the last section.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.599-608
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• 2004

New two kinds of methacrylate monomers having a benzene ring inserted between spacer and methacryloyl group and the chiral center connected to the terminal of the mesogenic structures were synthesized. In these two series the effects for the formation of the liquid crystals in regard to the length changes of the spacers and mesogenic groups were investigated. The first series did not show any liquid crystalline phases in the intermediate compounds nor in the end products. However, the methacrylates of second series showed the liquid crystalline phases in the intermediate compounds as well as in the final products regardless of the length of the spacers.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1125-1128
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• 2007

The laminating technique for developing flexible liquid crystal display was demonstrated by using a thin UV curable polymer film and a plastic substrate with patterned polymer wall structure. We adopted the rigid wall structure to provide a solid mechanical support for the stable molecular alignment of liquid crystals (LCs) in the device. The cover film was prepared to have an ability of aligning LC molecules by patterning a micro-groove structure using the soft-lithographic process. These two substrates can be assembled tightly by the laminating and one-step UV irradiation process because of the adhesive nature of the used UV curable polymers. Proposed method can be used to fabricate the flexible LC display with simplicity and also be applicable for a cost-effective roll-to-roll process.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.41-42
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• 2000

Photosensitive polyimides containing cinnamoyl and coumarin side groups were synthesized in a high molecular weight, giving a good quality of films. Nematic liquid-crystal (LC) molecules on the film were aligned along the direction with an angle of $97-99^{\circ}$ respect to the polarization of ultraviolet (UV) light. The LC alignment was induced mainly by the photoaligned polymer chains made by the first UV-exposure even though the film was treated by multiple exposures with changing the polarization of UV light. From these results, it is concluded that the LC alignment on the film is induced by the photodimerization rather than the trans-cis photoisomerization.

• Elastomers and Composites
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• v.44 no.4
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• pp.436-441
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• 2009

Semi flexible polyesters containing aromatic rings and pentamethylene groups in the main chain were synthesized by direct polycondensation reaction. The structures of these polymers were investigated by $^1H$-NMR and FT-IR and the phase transition behavior was characterized with DSC, TGA and crossed polarizing microscope. Inherent viscosities ($\eta_{inh}$) of polymers measured in phenol/p-chlorophenol/1,1,2,2-tetrachloroethane were between 0.46 and 1.30 dL/g. As increasing the linearlity of rigid moieties in polyster, melting transition temperatures ($T_m$) increased and solubilities in organic solvents decreased. P-H, P-mH and P-4H of the polymers formed turbid melts that showed stir-opalescence and nematic phase at the broad anisotropic region, However, P-R, P-C and P-2B did not exhibit any textures related to the liquid crystallinity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4041-4046
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• 2010

Wholly aromatic polyesters having flexible alkoxy side chain were synthesized by direct polycondensation. The synthetic polymers have been characterized by $^1H$-NMR, FT-IR. DSC, TGA, optical polarizing microscope and X-ray diffractometer. The inherent viscosities (${\eta}_{inh}$) measured in 1,1,2,2-tetrachloroethane (TCE) were 0.46~2.41 dL/g. The polymers having side chain showed double melting transition, ie, solid-sanidic liquid crystalline (LC) phase transition ($T_{m1}$) and sanidic LC phase-nematic LC phase transition ($T_{m2}$). As incresing length of alkoxy side chain, phase transition temperatures decreased and solubilities in organic solvents incresed. The peaks of $2{\theta}\;{\simeq}5$ and $2{\theta}\;{\simeq}20$ in X-ray diffractograms are due to crystallization of polymer main chain and of long side chain, respectively.

• Polymer(Korea)
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• v.31 no.5
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• pp.442-446
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• 2007

Alkali soluble and photo-curable polyesters were prepared from fluorene epoxy acrylate and various aromatic dianhydrides. To make a black matrix for LCD color-filter application, photo-resist solution was made by mixing synthesized polyester as binder, carbon black as pigment, initiator and multifunctional monomer in solvent. Black matrix pattern was formed on the glass substrate by lithography process. In this study, we synthesized various polyester-based binder polymers for LCD color-filter applications, and compared the analytical properties of those polymers and lithography patterns.