• 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.

• Journal of the Korean Applied Science and Technology
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• v.20 no.2
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• pp.177-181
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• 2003

Ultra-thin films of amphiphillic squarylium dye were prepared on the hydrophillic substrate by Langmuir-Blodgett(LB) technique. In this study, the photoelectric properties of a amphiphillic squarylium dye LB film was investigated. The visible light(${\lambda}$ = 684nm ) of xenon lamp was illuminated on the amphiphillic squarylium dye LB films and light absorptivity and photoconductivity were observed. The photoconductivity was nearly constant regardless of nominal layer number. The photoelectric properties of the amphiphillic squarylium dye LB films with bottom electrode showed better than that top electrode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.566-570
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• 2010

Electro-optic modulators based on 25 monolayer langmuir-blodgett films of vinylidene fluoride and trifluoroethylene, P(VDF-TrFE), were fabricated. The LB films were prepared by transferring the monolayers on to an ITO coated glass with a surface pressure of 5 dyne/cm by use of the langmuir-schaefer deposition method. Measurement of the electro-optic coefficient has been carried out using a simple reflection techique. The E/O coefficient was found to be 154.9 pm/V and that value remained stable for at least 50 days.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.359-366
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• 2014

We investigated an electrochemical properties for Langmuir-Blodgett (LB) films of saturated fatty acid and phospholipid(L-${\alpha}$-dimyristoylphosphatidyl choline, DMPC) mixture. LB films of saturated fatty acid and DMPC monolayer were deposited by the LB 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 $NaClO_4$ solution. As a result, monolayer LB films of saturated fatty acid and phospholipid mixture was appeared on irreversible process caused by the oxidation current from the cyclic voltammogram. Diffusion coefficient (D) of saturated fatty acid and DMPC mixture(molar ratio 1:1, C12, C14, C16, C18) was calculated $1.2{\times}10^{-3}$, $2.1{\times}10^{-3}$, $1.4{\times}10^{-4}$ and $1.1{\times}10^{-3}cm^2/s$ in 0.05 N $NaClO_4$ solution, respectively.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.55-62
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• 1998

The absorption spectra of polyamic acid containing p-methoxyazobenzene in a mixture of N, N-dimethylacetamide(DMAC) and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. This solution is influenced on temperature according to measure by UV-Vis Spectrophotometer. Ultra thin film of polyamic acid containing p-methoxyazobenzene was prepared on the hydrophilic quartz plate by Langmuir-Blodgett(LB) method. The precursor LB film was heated in a vacuum dry oven at $120^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.376-381
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• 2017

We were investigated by cyclic voltammetry to the stability through the electrochemical characteristics of Langmuir-Blodgett films mixed with myristic acid and stearic acid. Fatty acid mixture monolayer LB films was deposited by the LB method on the indium tin oxide(ITO) glass. The electrochemical properties was measured by cyclic voltammetry with a three-electrode system in 0.01 N $NaClO_4$ solution. The measuring range is continuously oxidized to 1650 mV, with an initial potential of -1350 mV was reduced. Scanning rates of 50, 100, 150, 200, and 250 mV/s was set. As a result, LB monolayer films of fatty acid mixture was appeared on irreversible processes by the oxidation current from the cyclic voltammogram. Diffusion coefficient (D) of fatty acid mixture was calculated $7.9{\times}10^{-2}cm^2s^{-1}$ at 0.01 N $NaClO_4$ solution.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.244-246
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• 1991

Recently, a study on LB ultra thin film of molecular size is widely performed. To make use of LB ultra thin film in engineering applications, it is important to investigate how uniformly Langmuir film is deposited on a substrate. In this paper, to confirm the uniformity of film deposition, the relation between the monolayer numbers deposited and its ratio is investigated by deposition of the Y type and Hetero type LB film. If films are deposited ideally, the deposition ratio will become 1.0. From the experimental results, it can be suggested that the deposition of LB film is done well, as we obtained an approximate value 1.0 by the calculation of deposition ratio of L film area and LB film deposition area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.353-356
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• 1999

The electrical characteristics of fatty acid LB films were investigated to develop the gas sensor using Langmuir-Blodgett(LB) films which have high ordered orientation and ordering structure. The deposition status of fatty acid LB films were verified by the measurements of UV absorbance. The conductivity of fatty acid LB films for horizontal direction at room temperature was about $10^8[S/cm]$,/TEX>, which was correspond to semiconductor material. The activation energy for fatty acid LB films with respect to variation of temperature was about l.O[eV]. The response characteristics for organic gas were confirmed by measuring the response time, recovery time, and reproducibility of the fatty acid LB films to each organic gas. Also, the penetration and adsorption behavior of gas molecule were confirmed through the organic gas response characteristics of fatty acid LB films with respect to temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.698-703
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• 2009

We report the studies on the structrural properties of Langmuir Blodgett (LB) films fabricated from the copolymer of vinylidenefluoride (VDF) with trifluoroethylene(TrFE). The formation of nanomesas induced by thermal annealing at $135\;^{\circ}C$ for 1 hour was investigated with the atomic force microscope (AFM) and the X-ray diffractometer (XRD). From the result of surface morphology change in 30 monolayer LB film, we find that the annealing treatment on the P(VDF-TrFE) LB film result in the plastic deformation of crystalline polymer. The ${\beta}$ phase crytalline structure in annealed LB film was clearly confirmed from the XRD peak at $19.7^{\circ}$.

• ETRI Journal
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• v.18 no.3
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• pp.195-206
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• 1996

Molecular conformations of stereoregular poly(methyl methacrylate) (PMMA) monolayers have been investigated by scanning probe microscopes. Isotactic and syndiotactic PMMAs were found to have right and left hand helical structures, respectively. On the contrary atactic PMMA showed rather random arrangement of the chains. It has been demonstrated that the PMMA Langmuir-Blodgett (LB) films can be utilized to form nanoscale patterns down to 50 nm and to forma geodesic lens. It has also been manifested that the quantum efficiency of a polymer electroluminescent device can be significantly enhanced by inserting the PMMA LB films between the emitting layer and the cathode. All the applications utilize the unique characteristics of the LB films to form thin and uniform films in the molecular level.