• Title/Summary/Keyword: Polyimide

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Electro-optical characteristics of TN-LCD on a Polyimide Surface Exposed to an Ion Beam (고분자 막을 이용한 이온빔 배향 TN-LCD의 전기광학특성)

  • Kim, Sang-Hoon;Hwang, Jeoung-Yeon;Kang, Hyung-Ku;Bae, Yu-Han;Lee, Whee-Won;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.271-272
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    • 2005
  • We studied liquid crystal (LC) alignment with ion beam (IB) on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide surface using obliquely ion beam exposure. A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the polyimide surface was observed. In addition, it can be achieved the good EO properties, and residual DC property of the ion-beam-aligned TN-LCD on polyimide surface.

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Effect of the Cl-based Plasma for Al Etching on the Interlayer Low Dielectric Polyimide (염소 플라즈마를 이용한 알루미늄 식각 공정이 저유전상수 층간절연막 polyimide에 미치는 영향)

  • 문호성;김상훈;이홍구;우상균;김경석;안진호
    • Journal of the Microelectronics and Packaging Society
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    • v.6 no.1
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    • pp.75-79
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    • 1999
  • We have studied electrical properties of polyimide for the next generation interlayer low dielectric during plasma etching. Dielectric constant of polyimide exposed to Cl-based plasma, which is used in aluminum etching, increased, while that of polyimide exposed to $SF_{6}$ plasma decreased. The results are related to fluorine or chlorine bonds as examined by FTIR ana XPS analyses. So, we expect that Cl-based 1)miasma etching of aluminum followed by $SF_{6}$ plasma exposure results in the prevention of post-etch corrosion and decrease of dielectric constant.

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Electrical Conductivity Behavior of 6FDA-based Fluorinated Polyimide/PMMA-g-MWCNT Nanocomposite Film (6FDA를 포함한 불소계 폴리이미드와 PMMA가 그래프트된 카본나노튜브 나노복합필름의 전기 전도성 연구)

  • Yun, Sung-Jin;Im, Hyun-Gu;Kim, Joo-Heon
    • Polymer(Korea)
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    • v.34 no.2
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    • pp.97-103
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    • 2010
  • PMMA was grafted on MWCNT surface in order to prepare conducting film composed of 6FDAbased polyimide/MWCNT. The electrical conductivity of 6FDA-based polyimide/PMMA-g-MWCNT was investigated as a function of PMMA-g-MWCNT content. Dispersion of MWCNT in 6FDA-based polyimide composite film was better than the pristine MWCNT due to the interaction force between PMMA and 6FDA-based polyimide. Electrical conductivity was interpreted by percolation threshold theory. As a result, 6FDA-6FpDA/PMMA-g-MWCNT which have high critical exponents and low critical concentration showed better dispersion than polyimide composite material that contains DABA(diamino benzoic acid).

TEM specimen preparation for observation of Cu oxides precipitated in the polyimide film and characterization of Cu oxide particles (폴리이미드박막내에 석출된 구리산화물 관찰을 위한 TEM 시편 제조와 구리산화물 분석)

  • You, Young-Sek;Kim, Young-Ho
    • Applied Microscopy
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    • v.25 no.1
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    • pp.130-138
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    • 1995
  • TEM specimen preparation methods have been examined to characterize Cu oxide particles in the polyimide film. Polyimide films were prepared by coating polyamic acid onto Cu films which had been deposited on TEM-mask and glass substrates and Cu foil, followed by thermal curing. In case of TEM-mask, direct observation was possible without further preparation. In other cases, TEM specimen were made by separating polyimide film from the substrate. Polyimide films were removed from glass and Cu foil by dissolving glass in HF solution and Cu foil in $H_{2}SO_{4}$ solution. TEM-mask observation confirms that fine $Cu_{2}O$ particles precipitate in the polyimide as a result of reaction of polyamic acid with Cu. However $Cu_{2}O$ particle reacts with HF and $H_{2}SO_{4}$ solution during dissolving the substrate and interpretation could be misled. It is concluded characterization of $Cu_{2}O$ particle in polyimide using TEM-mask is better than other methods.

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Positive-Type Photosensitive Polyimide Based on a Photobase Generator Containing Oxime-Urethane Groups as a Photosensitive Compound

  • Jang Young-Min;Seo Ji-Young;Chae Kyu-Ho;Yi Mi-Hye
    • Macromolecular Research
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    • v.14 no.3
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    • pp.300-305
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    • 2006
  • The chemical structure of a semi-aromatic polyimide-I, which was prepared by the chemical imidization of cyclopentanetetracarboxylic dianhydride and 2,2-bis(4-aminophenyl)hexafluoropropane, was characterized by $^{13}C-NMR$ spectroscopy. The chemically imidized polyimide-I was used for the preparation of a photosensitive polyimide (PSPI) through the addition of benzophenone and benzophenone oxime hexamethylene diurethane (BOHD), a photobase generator containing oxime-urethane groups. The polyimide-I film containing benzophenone and BOHD was not soluble in 2.38 wt% tetrabutylammonium hydroxide solution in $H_2O$. However, it became soluble following irradiation with 310 nm UV light. A positive tone image with a resolution of $5{\mu}m$ was obtained with this PSPI, having sensitivity($D_c$) of $1.2J/cm^2$ and contrast(${\gamma}_p$) of 1.08. Thus, a polyimide, which is not intrinsically photosensitive, can become photosensitive through the addition of a photobase generator containing oxime-urethane groups as a photosensitive compound.

Electro-optical Characteristics of Twisted Nematic(TN)-LCD using New Ion Beam Equipment (새로운 이온빔장치를 사용한 Twisted Nematic-LCD의 전기광학특성)

  • Kim Sang-Hoon;Hwang Jeoung-Yeon;Jang Mi-Hye;Kim Gwi-Yeol;Seo Dae-Shik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.6
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    • pp.547-551
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    • 2006
  • We studied liquid crystal (LC) alignment with ion beam (IB) on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide surface using obliquely ion beam (IB) exposure with new IB type equipment. A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the polyimide surface was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-LCD on polyimide surface. Also, the EO characteristics of the ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using new type IB equipment is same or more superior than ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using Kaufman-type Ar ion gun.

Effects of Thermal Imidization and Annealing on Liquid Crystal Alignment ever Rubbed Polyimide Layers: Change in the Pretilt Angle

  • Paek, Sang-Hyon
    • Macromolecular Research
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    • v.9 no.6
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    • pp.303-312
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    • 2001
  • The fabrication of liquid crystal display (LCD) panels involves several thermal processes such as imidization of the alignment layer (AL) and annealing of the rubbed polyimide AL. The nature of these processes on the LC alignment, especially on the pretilt angle (Θ$\_$p/) has been systematically studied, employing various types of polyimide structures. The imidization effect depends on the nature of polyimid precursors; Θ$\^$p/ increases with the degree of the imidization for the main-chain type of ALs, due to the decrease in the surface polarity, but this relation is not applicable to the alkylated ones in which the steric effect at the AL surface by the aliphatic side chains is dominant. Annealing of the rubbed polyimide AL deteriorates its rubbing-induced molecular orientation and subsequently the overlying LC alignment, resulting in the decrease in Θ$\_$p/. Especially, annealing of the LC cell affects the LC-AL interaction as well as the AL orientation and thus its effect on LC alignment depends sensitively on the nature of LC-polyimide interface; aromatic moiety in the polyimide structure gives better thermal stability of LC alignment while fluorinated polyimide ALs induce the less stable alignment.

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Ammonia Treatment of Polyimide Film (폴리이미드 필름의 암모니아 처리)

  • 김성훈
    • Textile Science and Engineering
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    • v.31 no.1
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    • pp.57-63
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    • 1994
  • High performance heat resistant polyimide film possesses high glass transition temperature, excellent mechanical property, chemical resistance, heat resistance and low thermal expansion However the polyimide after imidized from polyamic acid has a difficulty in deformation and poor adhesivity. The cyclized imide ring can be opened by ammonia at 3$0^{\circ}C$, and amide and amino groups can be produced. The ammonia treated polyimide may have better deformability and adhesivity. The imide ring opening by the ammonia treatment and the imide ring formation by second thermal imidization were confirmed by FT-IR and contact angle measurement. Tensile property and thermal stability were decreased with proceeding of the imide ring opening.

Optical Anisotropy of Polyimide and Polymethacrylate Containing Photocrosslinkable Chalcone Group in the Side Chain under Irradiation of a Linearly Polarized UV Light

  • Choi, Dong-Hoon;Cha, Young-Kwan
    • Bulletin of the Korean Chemical Society
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    • v.23 no.3
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    • pp.469-476
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    • 2002
  • Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy. The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

Nanostructuring the Polyimide Alignment Layer and Uniform Liquid Crystal Alignment by Solvent Assisted Micromolding (Solvent Assisted Micromolding을 이용한 Polyimide 나노구조 형성 및 이를 통한 균일 액정 배향)

  • Kim, Jongbok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.1
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    • pp.72-77
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    • 2019
  • The display that provides information to us through the visual sense is a very important information transmission means by intuitively transmitting information, and the liquid crystal display (LCD) is the most widely used information transmission display. In this paper, we studied solvent assisted micromolding as an alternative for the rubbing that is essential to align the liquid crystals in LCD and successfully aligned the liquid crystal molecules by constructing the nanostructures on conventional polyimide alignment layer. When generating the nanostructures on the polyimide film, there was a competitive correlation between the dissolution effect of the polymer by the solvent and the capillary effect of the polyimide molecules into the nanostructures of the mold depending on the process temperature. It was possible to form nanostructures with high step by deriving the optimum temperature. These nanostructures were able to align the liquid crystal molecules uniformly and demonstrated that they could form a desirable pretilt angle.