• Title/Summary/Keyword: photo-polymer

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Two photon absorption of electroluminescent polymer : Photoluminescence and photoconductivity studies (전기발광 고분자의 이광자흡수특성 : 광발광 및 광전도 특성)

  • Lee, Geon-Joon;Jeon, Seung-Joon;Kim, Kyung-Kon;Jin, Jung-Il;Kang, Han-Saem;Joo, Jin-Soo
    • Proceedings of the Optical Society of Korea Conference
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    • 2001.02a
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    • pp.228-229
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    • 2001
  • Electroluminescent polymers have attracted considerable attention due to possible applications as large-area light-emitting displays. There have been many efforts to improve the electroluminescent efficiency. To design the polymer with high efficiency, it is necessary to understand the luminescent mechanism. In this report, we have investigated two-photon absorption(2PA) characteristics of highly efficient electroluminescent polymer using various techniques such as nonlinear transmission, 2PA-induced photoluminescence(2PA-PL) and 2PA-induced photoconductivity(2PA-PC). (omitted)

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Fabrication of Micro Structure Using Photo Polymer Mask and Micro Abrasive Jet Machining (Photo Polymer 마스크와 미세입자분사가공을 이용한 미세구조물 제작)

  • Ko T.J.;Park D.J.;Lee I.H.;Kim H.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1175-1178
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    • 2005
  • Brittle materials, especially single-crystal silicon wafer, are widely used for sensors, IC industry, and MEMS applications. e general machining process of crack easy materials is by chemical agents, but it is hazardous and time consuming. Also, it is difficult to get high aspect ratio micro structure. As an alternative tool, an AJM(Abrasive jet machining) is promising method in terms of high aspect ratio and production cost. In this study, to get more precise detail compared to general AJM, photo polymer mask, SU-8, used in photolithography was applied in AJM. Process parameters such as abrasive diameter, air pressure, nozzle diameter, flow rate of abrasive in AJM and a variety of conditions in spin coating were decided. Finally, micro channel and mixer was fabricated to see the efficiency of the AJM with photo polymer mask.

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Optical Patterning and Applications of Photo-chromic Polymers (광변색 고분자의 광학적 패터닝과 응용)

  • Kim, Jun-Young;Fukuda, Takashi
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.76-76
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    • 2007
  • Several kinds of photo-chromic polymers containing push-pull structure were synthesized and investigated on optical patterning by photo-induced surface relief gratings (SRG) technique. The azobenzene segment was introduced as a functional group for a photo-triggered tran-cis isomerization. Consequently, we have fabricated micro-size regular pattern by one-step process without photo-mask.

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Solution processed organic photodetector utilizing an interdiffused polymer/fullerene bilayer

  • Shafian, Shafidah;Jang, Yoonhee;Kim, Kyungkon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.348-348
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    • 2016
  • Low dark current (off-current) and high photo current are both essential for a solution processed organic photodetector (OPD) to achieve high photo-responsivity. Currently, most OPDs utilize a bulk heterojunction (BHJ) photo-active layer that is prepared by the one-step deposition of a polymer:fullerene blend solution. However, the BHJ structure is the main cause of the high dark current in solution processed OPDs. It is revealed that the detectivity and spectral responsivity of the OPD can be improved by utilizing a photo-active layer consisting of an interdiffused polymer/fullerene bilayer (ID-BL). This ID-BL is prepared by the sequential solution deposition (SqD) of poly(3-hexylthiophene) (P3HT) and [6,6] phenyl C61 butyric acid methyl ester (PCBM) solutions. The ID-BL OPD is found to prevent undesirable electron injection from the hole collecting electrode to the ID-BL photo-active layer resulting in a reduced dark current in the ID-BL OPD. Based on dark current and external quantum efficiency (EQE) analysis, the detectivity of the ID-BL OPD is determined to be $7.60{\times}1011$ Jones at 620 nm. This value is 3.4 times higher than that of BHJ OPDs. Furthermore, compared to BHJ OPDs, the ID-BL OPD exhibited a more consistent spectral response in the range of 400 - 660 nm.

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Fabrication and electro optical properties of stressed liquid crystal cell

  • Lee, Jung-Min;Park, Jin-Seol;Kang, Dae-Seung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.681-682
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    • 2009
  • We fabricated a stressed liquid crystal cell by mixing liquid crystal with a photo-polymer. By carefully choosing the mixing ratio between liquid crystal and the polymer, and by suitable mechanical shearing of the substrates, we demonstrated feasible electro optical properties for displays.

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Photo-Crosslinking of Poly(glycidyl methacrylate) Initiated by N-Hydroxyphthalimide Sulfonates

  • Kyu Ho Chae;Ik Ju Park;Min Ho Choi
    • Bulletin of the Korean Chemical Society
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    • v.14 no.5
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    • pp.614-618
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    • 1993
  • The photoacid generation efficiency of four N-hydroxyphthalimide sulfonate derivatives was studied by photo-crosslinking reaction of poly(glycidyl methacrylate) in solid film state. The relative photoacid generation efficiency was increased in the order of N-hydroxyphthalimide methanesulfonate > -toluenesulfonate > -nitrobenzenesulfonate > -dinitrobenzensulfonate, and the reaction was efficiently sensitized by benzophenone suggesting that this photoreactions is likely to proceed through its triplet excited state.

Liquid crystal alignment effect and synthesis of photo-polymer material containing cholesteryl moiety for homeotropic alignment (Cholesteryl 기를 함유한 수직배향용 광폴리머 재료의 합성 및 배향 효과)

  • 황정연;서대식;한은주
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.9
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    • pp.770-775
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    • 2000
  • A new photo-polymer material of the copoly (PM4Ch-ChMA), copoly (poly (4-methacryloyloxy)chalcone-cholesteryl methacrylate) for homeotropic alignment was synthesized and the electro-optical (EO) performance for the photo-aligned vertical-aligned (VA)-LC display (LCD) was studied. Good thermal stabilities of synthesized copolymer were obtained by TGA(Thermogravimetric Analysis) measurement. Good voltage-transmittance (V-T) and response time characteristics for the photo-aligned VA-LCD with polarized UV exposure in oblique direction($\theta$$_{i}$=30$^{\circ}$) on a copolymer-1 (2%) surfaces for 1 min were observed. but, light leakage in the off-state was observed. Therefore, we achieved excellent V-T and response time characteristics for the photo-aligned VA-LCD with UV exposure on a copolymer-3 (30%) surfaces for 3 min.n.

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Curing and Surface Properties of UV-curable Coating Containing Wax (왁스를 함유한 자외선 경화형 코팅제의 경화 및 표면 물성)

  • Han, A-Ram;Kim, Jong-Gu;Hong, Jin-Who;Kim, Hyun-Kyoung
    • Journal of Adhesion and Interface
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    • v.13 no.1
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    • pp.38-44
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    • 2012
  • Surface properties and curing behavior of UV-initiated photopolymerization with and without wax have been investigated by pendulum hardness, pencil hardness, gloss, photo-differential scanning calorimetry (photo-DSC) and SEM. In addition, the influence of wax type (paraffin wax, PE wax) on the various properties of UV cured films was studied. The results showed that the wax type was the significant factor affecting gloss and surface hardness of UV cured films. Specially, the photo-DSC results showed that ${\Delta}H$ for the UV cured films containing paraffin wax was higher than the corresponding values for the formulation without wax and with PE wax. The observed results clearly demonstrate that the photopolymerization of UV curing with paraffin wax in an air atmosphere is less inhibited by the oxygen compared to UV curing without wax and with PE wax.

Photo-Alignment Mechanism Study of Poly(siloxane cinnamate) (폴리(실록산 신나메이트)의 광배향 메커니즘 연구)

  • Choi Ji-Won;Lim Ji-Chul;Song Ki-Gook
    • Polymer(Korea)
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    • v.30 no.5
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    • pp.417-421
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    • 2006
  • Photo -alignment of poly (siloxane cinnamate) (PSCN) was studied to better understand the alignment mechanism of cynnamoyl groups under various process conditions. DSC and polarized microscope studies showed that the isotropic temperature oi PSCN was about $105^{\circ}C$ and the liquid crystallinity, once formed, did not completely disappear even when the temperature went into the isotropic regions. UV/Vis absorption study suggested that the photo - dimerization was the main photo alignment mechanism and it's efficiency could be enhanced through the self-alignment of PSCN. It was also found that photo-dimerization was in competition with photo-fries reaction and the photo- alignment of PSCN was interfered with the excessive UV because of the strong photo-fries reaction. However, photo - fries reaction could be suppressed by adjusting the UV wavelength.

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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    • v.17 no.12
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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.