• 제목/요약/키워드: polymer stability

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Synthesis and Properties of Novel T-type Nonlinear Optical Polyurethane Containing Tricyanovinylthienyl Group with Enhanced Thermal Stability of Dipole Alignment

  • Cho, You-Jin;Kim, Mi-Sung;Lee, Ju-Yeon
    • Bulletin of the Korean Chemical Society
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    • 제32권2호
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    • pp.424-430
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    • 2011
  • A novel T-type polyurethane 7 containing 1-(2,5-dioxyphenyl)-2-(5-(1,2,2-tricyanovinyl)-2-thienyl)ethenes as NLO chromophores, which constitute part of the polymer backbone, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It shows a thermal stability up to $270^{\circ}C$ from TGA thermogram with $T_g$ value obtained from DSC thermogram near $155^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer film at 1560 nm fundamental wavelength is $3.56{\times}10^{-9}$ esu. Polymer 7 exhibits a thermal stability even at $5^{\circ}C$ higher than $T_g$, and no significant SHG decay is observed below $160^{\circ}C$, which is acceptable for nonlinear optical device applications.

Preparation and characteristics of conducting polymer-coated multiwalled carbon nanotubes for a gas sensor

  • Jang, Woo-Kyung;Yun, Ju-Mi;Kim, Hyung-Il;Lee, Young-Seak
    • Carbon letters
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    • 제12권3호
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    • pp.162-166
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    • 2011
  • Conducting polymer-coated multiwalled carbon nanotubes (MWCNTs) were prepared by template polymerization in order to enhance their gas sensitivity. This investigation of the conducting polymer phases that formed on the surface of the MWCNTs is based on field-emission scanning electron microscopy images. The thermal stability of the conducting polymer-coated MWCNTs was significantly improved by the high thermal stability of MWCNTs. The synergistic effects of the conducting polymer-coated MWCNTs improve the gas-sensing properties. MWCNTs coated with polyaniline uniformly show outstanding improvement in gas sensitivity to $NH_3$ due to the synergistic combination of efficient adsorption of $NH_3$ gas and variation in the conduction of electrons.

Optically Compensated Bend Cell with Pixel-Isolating Polymer Wall for a Flexible Display Application

  • Lee, Seong-Ryong;Lee, Joong-Ha;Jang, Hong-Jeek;Yoon, Tae-Hoon;Kim, Jae-Chang
    • Journal of Information Display
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    • 제8권4호
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    • pp.5-9
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    • 2007
  • We demonstrate an optically compensated bend (OCB) cell with pixel-isolating polymer wall. The polymer wall is formed by anisotropic phase separation of LCs and UV-curable polymer. The fabricated cell is initially in ${\pi}-twisted$ state so that it shows uniform and fast bend transition without any transition nucleus. The proposed cell has lower driving voltage than conventional OCB cell. Also, the polymer wall provides mechanical stability, hence preventing distortion of display image from external pressure.

$Orgacon^{TM}$ - The Organic alternative to ITO

  • Louwet, Frank
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.193-194
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    • 2008
  • $Orgacon^{TM}$ products, based on the conducting polymer PEDOT/PSS, are very promising materials in cost-effective R2R production of large area electronics. This presentation will show both the progress in the surface resistance/VLT and progress in the stability (T/R.H. and light stability). A new generation of films, coating formulations and inks will be presented.

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Electro-Optic Devices Based on Ferroelectric Liquid Crystal/Polymer Composite Films

  • Park, Jae-Hong;Kim, Sung-Jin;Lee, Won-Je;Kim, Jae-Hoon;Lee, Sin-Doo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.910-913
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    • 2002
  • We have achieved an improved stability of an analog electro-optic effect in FLC/polymer composite films. The optimization of device depends on both the composition of the FLC/polymer mixture and the energy of UV irradiation. This device exhibits continuous gray scales and the mechanical stability against external forces.

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Spacing Method Suitable for Flexible Cholesteric LCDs

  • Yoon, Hyun-Sub;Min, Kwan-Sik;Kwon, Soon-Bum
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.484-487
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    • 2005
  • In order to find out LC cell spacing method suitable for flexible cholesteric LCDs with high mechanical stability, we carried out bending and mechanical shock tests by using various spacing techniques: bead spacer, photo spacer, polymer wall with bead spacer and polymer wall with photo spacer. As a result, it was found that the spacing method using polymer wall incorporated with photo spacer is the best for flexible cholesteric LCDs in terms of mechanical stability. The investigation is discussed in detail.

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Synthesis and Nonlinear Optical Properties of Novel Y-Type Polyesters with Enhanced Thermal Stability of Second Harmonic Generation

  • Kim, Jin-Hyang;Lee, Ju-Yeon;Won, Dong-Seon;Rhee, Bum-Ku
    • Macromolecular Research
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    • 제15권6호
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    • pp.506-512
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    • 2007
  • 2,3-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (3) was prepared and condensed with terephthaloyl chloride, adipoyl chloride, and sebacoyl chloride to yield novel Y-type polyesters (4-6) containing the NLO-chromophores 2,3-dioxynitrostilbenyl groups, which constituted parts of the polymer backbones. Polymers 4-6 were soluble in common organic solvents such as acetone and N,N-dimethylformamide. Polymers 4-5 showed thermal stability up to $300^{\circ}C$ in thermogravimetric analysis with glass transition temperatures $(T_g)$, obtained from differential scanning calorimetry, in the range $81-95^{\circ}C$. The second harmonic generation (SHG) coefficients $(d_{33})$ of the poled polymer films at the 1064 nm fundamental wavelength were around $3.68{\times}10^{-9}$ esu. The dipole alignment exhibited high thermal stability up to $T_g$, and there was no SHG decay below $T_g$ due to the partial main-chain character of the polymer structure.