• Title/Summary/Keyword: Langmuir-films

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The electrical properties of Polyimide Langmuir-Blodgett Film (Polyimide LB막의 전기적 특성)

  • 박준수;이호식;김태완;손병철;강도열
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.05a
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    • pp.111-114
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    • 1995
  • This paper describes the imidization of PAAS(polyamic acid alkylamine salts) Langmuir-Blodgett (LB) films and the electrical properties of PAAS and polyimide(PI) LB films, The imidization conditons were investigated by TGA(Thermal Gravi-tational Analysis). FT-IR and UV/ visible absorption spectra. A thermal imidiczation was peformed at 300$^{\circ}C$ for 1 hour. The electrical properties of the PAAS and polymide LB films were measured by current-voltate(L-V) characteristics It shows that the electrical condcutivity of PL LB films is about 10 $\^$-15/S/cm which is two orders of magnetiude lower than that of the PAAS LB films A Schottky effect was also observed in both films.

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A Study on the Electrochemical Properties of Langmuir-Blodgett Nano-film Mixed with Polyimide and Phospholipid (폴리이미드와 인지질 혼합물의 나노 Langmuir-Blodgett막의 전기화학적 특성에 관한 연구)

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.3
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    • pp.421-428
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    • 2012
  • We investigated an electrochemical properties for Langmuir-Blodgett (LB) nano-films of polyimide and phospholipid mixture. LB films of polyamic acid and phospholipid monolayer were deposited by the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured by cyclic voltammetry with three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) in $KClO_4$ solution. The current of reduction and oxidation range was measured from 1650 mV to -1350 mV, continuously. The scan rates were 50, 100, 150, 200 and 250 mV/s, respectively. As a result, monolayer LB films of polyamic acid and phospholipid mixture was appeared on irreversible process caused by the reduction current from the cyclic voltammogram. Diffusion coefficient (D) effect in the polyamic acid and phospholipid mixture was used in the LAPC with LLPC fewer than the diffusion coefficient values.

Mono- and Multi-layer Langmuir-Blodgett Films of Maleimide Polymers Possessing Nonlinear Optical-Active Side Chains

  • Yoon Kuk Ro;Lee Hoosung;Rhee Bum Ku;Jung Changsoo
    • Macromolecular Research
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    • v.12 no.6
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    • pp.581-585
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    • 2004
  • A copolymer P[OSA-MI] was synthesized by copolymerization of its corresponding monomers, N-phenyl maleimide (MI) and 2-octen-l-ylsuccinic anhydride (OSA). The polymer (poly[2-[1-(2,5-dioxo-l-phenylpyrroli­din-3-ylmethyl)heptyl]-succinic acid 4-(2-$\{$ethyl-[4-(4-nitrophen-ylazo)phenyl]amino$\}$ethyl)ester]) P[DR1MA-MI] was obtained from the reaction of P[OSA-MI] with 2-[4-(4-nitrophenylazo)-N-ethylphenylamino] ethanol (DR1). A stable monolayer of P[DRIMA-MI] was formed by spreading the solution of the polymer in chloroform. In Y-type Langmuir-Blodgett (LB) films prepared using this Langmuir-Blodgett method, the second harmonic waves generated from adjacent mono layers canceled each other out. In X-and Z-type LB films, the second harmonic intensity increased upon increasing the number of monolayers, but this increase was somewhat smaller than predicted by the square law. This phenomenon is due to defects or imperfect alignment of the dipoles in the LB film. The generation of second harmonic waves from Y-type LB films having an even number of mono layers supports this argument. The degree of imperfection seemed to increase as the number of layers increased. The second-order nonlinear optical properties of spin-cast films of these polymers were also measured. The largest second harmonic coefficient of the poled P[DRIMA-MI] film coated on a glass plate was 19 pm/V.

Electrochemical Properties of Langmuir-Blodgett(LB) Films of Fatty Acid Containing Azobenzene and $L-{\alpha}-dimyristoylphosphatidylcholine$ Mixture (아조벤젠기를 가진 지방산과 $L-{\alpha}-dimyristoylphosphatidylcholine$ 혼합 LB막의 전기화학적 특성)

  • Park, Keun-Ho;Choi, Sung-Hyun;Song, Ju-Yeong
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.4
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    • pp.315-322
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    • 2005
  • We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and $phospholipid(L-{\alpha}-dimyristoylphosphatidylcholine$, denoted as DMPC). LB films of 8A5H monolayer and 8A5H-DMPC were deposited by using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured by using cyclic voltammetry with a three_electrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0mol/L) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rates were 50, 100, 150 and 200mV/s, respectively. As a result, LB films of 8A5H monolayer appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC mixture were found to be caused by a reversible oxidation-reduction process.

Electric Characteristics of Fatty Acid LB Films for Change of Temperature (은도 변화에 대한 지방산 LB막의 전기적 특성)

  • 이준호;김도균;최용성;장정수;권영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.167-170
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    • 1998
  • The electrical characteristics of Stearic acid LB films were investigated to develop the gas sensor using Langmuir-Blodgett(LB) films. The deposition status of LB films were verified by the measurements of UV absorbance and I-V characteristics. The conductivity of Stearic acid LB films at room temperature was $10^{-8}[S/cm]$, which is typical of semiconductor. The conductivity was found to increase as the temperature was increased. The acitivation energy was about 1[eV].

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Synthesis of (N-docosyl pyridinium)-TCNQ (1:1) Complex and Negative Resistance Phenomena in Langmuir-Blodgett Ultra Thin Films ((N-docosyl pyridinium)-TCNQ(1:1) 착체의 합성과 Langmuir-Blodgett 초박막에서 부성저항현상)

  • Seo, T.S.;Choi, M.K.;Lee, W.J.;Shon, B.C.;Kwon, Y.S.;Kang, D.Y.
    • Proceedings of the KIEE Conference
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    • 1989.11a
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    • pp.105-108
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    • 1989
  • For the purpose of fabricating of LB Ultra Thin Films. (N-docosyl pyridinium)-TCNQ(l: 1) Complex is synthesized. This specimen is verified by U.V. I.R and elemental analyzer. In fabricated LB films with this, as a measurements of electrical conduction characteristics in perpendicular direction, this films have characteristics of insulator(about $10^{-14}S/cm$). And negative resistance phenomena are observed in I-V characteristics of this films.

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