• 제목/요약/키워드: Oriented Polymer

검색결과 88건 처리시간 0.022초

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • 제17권12호
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

Polymeric Flexible Field Effect Transistors using Oriented Poly(3-hexylthiophene-2,5-diyl)

  • Lee, Yeong-Beom;Shim, Hong-Ku
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.637-640
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    • 2008
  • The properties of oriented poly(3-hexylthiophene-2,5-diyl) in field effect transistors (FETs) have been investigated through mechanical stretching process as the original. Silicon-based FETs shown high mobility of $0.02\;cm^2/V$ s after thermal treatment and $0.0092\;cm^2/V$ s at r.t. PET-based FETs were expected to show a similar performance in mobility to that of silicon-based FETs.

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상업용 고분자 필름의 산소투과도 및 산소투과 방지도에 관한 연구 (Studies on the Oxygen Permeability and It's Proofness of the Various Commercial Polymer Films)

  • 서환규;김준수;이정근
    • Elastomers and Composites
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    • 제15권1호
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    • pp.3-9
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    • 1980
  • 일정온도와 압력에서 상업용 고분자필름들의 산소투과도와 산소투과방지도에 관하여 연주하였다. 산소투과방지 도는 산소특과도의 역수로 정의하고 coulometric oxygen permeability tester를 사용하여 $23{\pm}1^{\circ}C$, latm에서 24시간 동안 투과한 산소의 량을 측정하였다. 산소투과방지도의 상대적 크기는 다음과 같은 순서로 감소함을 밝혔다. 연신 Nylon (O. Nylon)> 연신 Polyester (O. PET)> 무연신 Nylon (N. Nylon)> 무연신 Polyester(N. PET)> 경질 Polyvinyl chloride (Rigid PVC)> 반경질 Polyvinyl chloride (Semirigid PVC)> 연신 Polypropylene (O. PP)> 연질 Polyvinyl chloride (P. PVC)> 무연신 Polypropylene (C. PP)> 저밀도 Polyethylene(LDPE)> 고밀도 Polyethylene (HDPE, Inflation)> 고밀도 Polyethylene (HDPE, T-die) 필름들의 산소투과방지도는 고분자의 극성, 필름의 두께 및 기계적 연신성의 증가에 따라서 증가하고 PVC에서는 가소제 첨가에 따라서 감소하였다. 포장재료로서 고분자 필름은 고분자 주쇄에 극성이 있는 필름과 극성이 없는 필름들을 산소 및 습기투과방지를 위하여 첩합하여야 한다.

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SHG을 이용한 LCD 배향막 표면 특성분석 (Surface characterization of polyimides for LCDs by second-harmonic generation technique)

  • 정태혁;윤태훈;김재창
    • 전자공학회논문지D
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    • 제34D권3호
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    • pp.114-122
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    • 1997
  • The surface characteristics of polymers for liquid crystal alignment are studied by optical second-harmonic genertion (SHG) tecnique. Using SHG technique, the LC monolayers on rubbed polymer have already been studied. But, in this paper, the SH signals of polymer were observed and the orientational distribution of oriented polymer was studied. Te SHG experiments for side-chain type and main-chain type polymers are carried out as a function of rubbing strength. The orentational distribution of surface molecules of polymers is compared with the LC pretilt angle measured by the crystal rotation method.

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PHYSICAL PROPERTIES OF HIGHLY-ORIENTED POLYVINYLALCOHOL FIBER

  • Kim Byeong-Cheol;Im Seung-Sun;Kim Seung-Gyu;Han Jeong-Ryeon
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 1998년도 가을 학술발표회논문집
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    • pp.223-226
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    • 1998
  • Polyvinylalcohol (PVA) is a crystalline polymer, capable of hydrogen bonding, which makes the polymer useful for many industrial applications. production of high strength fibers, medical substitutes, adhesives, and so on[1], Specially, among fiber-forming polymers, PVA has the second highest crystal modulus and extreme strength after polyethylene because the polymer chain can take a planar zig-zag conformation. (omitted)

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Fabrication of Conducting Polymer Nanowires using Block Copolymer Nano-porous Templates for Photovoltaic Device

  • Lee, Jeong-In;Yu Jae-Woong;Kim, Jin-Kon;Russell Thomas P.
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.312-312
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    • 2006
  • Block copolymers with well-defined nanoscopic structures have recently gained much attention for their potential uses as functional nanostructures. Here, we show that nanoporous templates made from polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) satisfy a novel design concept. At first, arrays of nanoscopic cylindrical microdomains oriented normal to the surface can easily be prepared. Then, we fabricated ultra high density arrays of conducting polymer as poly(pyrrole) (Ppy) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires with diameters of $25{\sim}40\;nm$ on the ITO glass by electropolymerization of the monomers inside nanoholes. These high density arrays of conducting polymer nanowires could be used as P-type materials for photovoltaic devices.

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Nanostructure formation in thin films of block copolymers prepared by controlled radical polymerization

  • Voit, B.;Fleischmann, S.;Messerschmidt, M.;Leuteritz, A.
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.99-100
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    • 2006
  • Orthogonally protected block copolymers of based on p-hydroxystyrene were prepared with high control via nitroxy mediated radical polymerization using an alkoxyamine as an unimolecular initiator. Thin films of partially protected block copolymer were prepared by spin or dip coating. A well defined nanostructure could be observed as a result of phase separation e.g. cylinders in a matrix oriented perpendicular or parallel to the substrate. The nanostructure of the polymeric films can be defined by the block copolymer composition and it determines surface properties and allows further, selective functionalization, e.g. via click chemistry. The thin films can be designed in a way to allow a patterning based on a thermal or photochemical stimulus.

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Design-oriented strength and strain models for GFRP-wrapped concrete

  • Messaoud, Houssem;Kassoul, Amar;Bougara, Abdelkader
    • Computers and Concrete
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    • 제26권3호
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    • pp.293-307
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    • 2020
  • The aim of this paper is to develop design-oriented models for the prediction of the ultimate strength and ultimate axial strain for concrete confined with glass fiber-reinforced polymer (GFRP) wraps. Twenty of most used and recent design-oriented models developed to predict the strength and strain of GFRP-confined concrete in circular sections are selected and evaluated basing on a database of 163 test results of concrete cylinders confined with GFRP wraps subjected to uniaxial compression. The evaluation of these models is performed using three statistical indices namely the coefficient of the determination (R2), the root mean square error (RMSE), and the average absolute error (AAE). Based on this study, new strength and strain models for GFRP-wrapped concrete are developed using regression analysis. The obtained results show that the proposed models exhibit better performance and provide accurate predictions over the existing models.

소비자 지향 3차원 헬멧제품 제작을 위한 UV레이저 기반의 폴리머/금속적층에 대한 기초연구 (A Fundamental Study on Polymer/Metal Additive Method using a UV Laser for Consumer-oriented 3D Helmet Products)

  • 강보석;안동규;신보성;신종국
    • 한국기계가공학회지
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    • 제15권6호
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    • pp.89-94
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    • 2016
  • Consumer orientation requires that companies understand consumer needs and produce products that meet their expectations. This study proposes a new additive method that creates a polymer/metal bonding layer and thus can lighten the weight of helmets to develop a consumer-oriented 3D printing helmet. The composite solution is experimentally prepared with copper formate and a photopolymer resin. Stereolithography apparatus and photothermal reactions are introduced to fabricate an adhesive hybrid layer of copper metal and polymer. A UV pulse laser with a 355 nm wavelength was installed to simplify this process. Resistance, adhesion, and accuracy were investigated to evaluate the properties of the layer produced.