• 제목/요약/키워드: Polymer science

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고전기장을 이용한 도전성 탄소섬유/폴리에틸렌 복합필름의 제조 및 특성 연구 : 고분자 점착하층의 영향 (Fabrication and Properties of Conductive Carbon Fiber/Polyethylene Composite Films Fabricated under High Intensity Electric Fields : Effect of Polymer Sublayer)

  • 박민;김준경;임순호;고문배;최철림;;방효재;이광희
    • 폴리머
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    • 제24권2호
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    • pp.268-275
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    • 2000
  • 고전기장을 이용하여 제조한 도전성 탄소섬유/폴리에틸렌 복합필름에 있어서 고분자 점착하층의 두께가 제조된 필름의 체적비저항과 인장강도에 미치는 효과에 대하여 연구하였다. 탄소섬유(CF) 함량과 CF 층밀도에 따라 제조된 필름의 체적비저항과 인장강도의 점착하층에 대한 의존성의 양상은 복잡하게 나타났다. 이는 점착하층의 증가에 따라서 필름 하층면에 중심부나 위쪽에 비하여 CF 농도가 낮은 절연성 고분자층의 두에가 증가하고 필름 상층면 근처에서는 CF의 함침에 필요한 고분자 매트릭스의 양이 적어져 매트릭스 함침이 불충분하여 기공이 포함된 구조를 형성시키는 효과와 증가된 매트릭스의 유동성을 바탕으로 CF 분산성이 향상되고 동시에 보다 치밀한 구조가 형성되는 두 가지 상반되는 효과의 상대적 기여 정도의 차이를 통하여 설명할 수 있었다. 이들 결과는 전자파 차폐용 고도전성 고분자 차폐필름의 제조에 있어서 전기적 성질과 기계적 성질의 최적화하는데 중요하다.

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이형질적 이중구조로 분석한 피부에서의 클로니딘 투과기전 (Mechanism of Clonidine Permeation through Skin Based on Heterogeneous Structure)

  • 변영로;김영하;정서영
    • Journal of Pharmaceutical Investigation
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    • 제19권1호
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    • pp.39-46
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    • 1989
  • The clonidine transport mechanism through the skin was investigated with assumptions that epidermis is heterogeneous and two-layer membrane. Immobilization of clonidine was not found in stratum corneum but in viable epidermis. The sorption in the viable epidermis agreed with the dual sorption theory. Diffusion coefficient in stratum corneum was five order magnitude less than that in viable epidermis. In viable epidermis, the ratio of true diffusivity to apparent diffusivity increased initially then decreased as a function of clonidine concentration, and the true diffusivity was always larger than the apparent diffusivity.

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Reduction of an Operating Voltage of Liquid Crystal Display based on Kerr Effect

  • Kim, Min-Su;Kim, Mi-Young;Kang, Byeong-Gyun;Kim, Mi-Kyung;Yoon, Su-Kin;Choi, Suk-Won;Lee, Gi-Dong;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.637-640
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    • 2009
  • The LCD based on Kerr effect is highly interesting because it uses an optically isotropic state with no need of alignment layer and it shows sub-millisecond response time. The problem of the device is that it requires very high operating voltage and the transmittance is relatively low compared with other LCDs that use nematic LC. In this work, we study on various electrode structures and driving method which can lower operating voltage.

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Thickness Dependence of the Glass Transition Temperature in Thin Polymer Films

  • Lee, Jeong-Kyu;Zin, Wang-Cheol
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.201-201
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    • 2006
  • In this study the glass transition temperature in thin polymer films has been studied. Ellipsometry has been used to measure $T_{g}$ of thin film as a function of film thickness. Empirical equation has been proposed to fit the measured $T_{g}$ pattern with thickness. Also, a continuous multilayer model was proposed and derived to describe the effect of surface on the observed $T_{g}$ reduction in thin films, and the depth-dependent $T_{g}$ profile was obtained. These results showed that $T_{g}$ at the top surface was much lower than the bulk $T_{g}$ and gradually approached the bulk $T_{g}$ with increasing distance from the edge of the film. The model and equation were modified to apply for the polymer coated on the strongly favorable substrate and the freely standing film.

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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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Positive Type Photoresist for Patterning of Interdielectric Layer of TFT Array

  • Lee, Hyo-Jung;Kim, Hyo-Jin;Kim, Soon-Hak;Park, Lee-Soon;Lee, Yun-Su;Song, Gab-Deuk
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.564-566
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    • 2007
  • Synthesis of two photoactive compounds containing core imide moiety was carried out for an application to interdielectric layer in TFTLCD array. An aqueous alkaline developable polymer matrix was synthesized by free radical copolymerization. A positive photoresist formulation was developed utilizing synthesized UV monomers, photoactive compound, binder polymer, sulfactant and alkali developable polymer matrix. It was found that via-holes with good resolution, high transmittance and thermal resistance could be obtained by photolithographic process utilizing the new positive interdielectric material with high thermal stability.

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Temperature Controllable HPLC Column for Preparative Fractionation of Polymers

  • Im, Kyu-Hyun;Park, Hae-Woong;Kim, Young-Tak;Chang, Tai-Hyun
    • Macromolecular Research
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    • 제16권6호
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    • pp.544-548
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    • 2008
  • An HPLC column with a self-contained temperature control device was constructed for preparative temperature programmed interaction chromatography. Two Peltier plates were attached to a large bore column ($120{\times}22\;mm$ i.d.) and the column temperature was controlled by PID mode feed back control. At a flow rate of 1.5 mL/min, the column temperature could be increased and decreased at a rate as high as $50^{\circ}C/min$ and $10^{\circ}C/min$, respectively, which is much faster than using a column jacket and bath/circulator. The rapid heating and cooling rates allows a high repetition rate of chromatographic fractionation. The performance of the temperature controllable column was demonstrated successfully by the fractionation of homo-polymer precursors from diblock copolymers.

Lithographic Microfabrication for Nano/Micro-Objects by using Two-Photon Polymerization Technique

  • Lee, Kwang-Sup;Kang, Seung-Wan;Kim, Ran-Hee;Kim, Ju-Yeon;Kim, Won-Jin;Park, Sang-Hu;Lim, Tae-Woo;Yang, Dong-Yol;Sun, Hong-Bo;Kawata, Satoshi
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.15-16
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    • 2006
  • Since two-photon polymerization (TPP) emerged as a new technology over a decade ago, a large variety of micro-objects including 3-D micro-optical components, micromechanical devices, and 3-D photonic crystals have been fabricated using TPP with a high spatial resolution of approximately submicron scale to 100 nm. Recent efforts have been made to improve the fabrication efficiency and precision of micro-objects obtained with TPP; in particular, many studies have been carried out with the aim of developing efficient two-photon absorbing chromophores. In this presentation, we will discuss our efforts to develop highly efficient two-photon absorbing materials and also describe recent attempts to enhance the resolution and to improve the fabrication efficiency of nanofabrications based on TPP.

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LC Alignment Behaviors at Rubbed Films of Brush Polyimides;Perpendicular LC Alignment versus Parallel LC Alignment

  • Lee, Taek-Joon;Hahm, Seok-Gyu;Lee, Seung-Woo;Chae, Bok-Nam;Lee, Seong-June;Kim, Seung-Bin;Jung, Jin-Chul;Ree, Moon-Hor
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.766-768
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    • 2004
  • Rubbed films of a series of poly(p-phenylene 3,6-bis(4-(n-alkyloxy)phenyloxy)pyromellitimide)s (Cn-PMDA-PDA PIs), which are well-defined brush PIs composed of two aromatic-aliphatic bristles per repeat unit of a fully rodlike backbone, were investigated in detail using atomic force microscopy (AFM), optical retardation analysis and linearly polarized infrared (IR) spectroscopy in order to elucidate their surface morphology and molecular orientation. The liquid crystal (LC) alignment behavior and the anchoring energy of LC molecules on the rubbed films were also determined.

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