• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.52-54
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• 2006

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multi layers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.358-359
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• 2006

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multilayers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.75-85
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• 1996

The absorption spectra of synthesis of long chain fatty acid containing azobenzene start from p-(p'-hydroxy phenyl azo)-benzoic acid was investigated by ultraviolet spectrophotometery in chloroform solvent at the various temperature. In addition, The pressure-area of the water-air interface was obtained and the LB film was fabricated onto a quartz slide and quartz crystal by conventional Langmuir-Blodgett(LB) method. The UV absorption spectra of Langmuir-Blodgett(LB) film on quartz slide and spectrum of monolayer formed on quartz crystal have been measured. Long chain fatty acid containing azobenzene are induced phtoisomerization by the application of u. v. and visible light irradiation alternatively the reversibility of phtoisomerization was more clear difference when the number of $C_{n}$ increased but, not so good at $C_{14}-azo$. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_{n}$ increased. A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were induced by application of UV and visible light irradiation alternatively. So the LB film of long chain fatty acid containing azobenzene has possibility to being applied to functional molecular devices such as photomemory and light switching.

• 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.27 no.2
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• pp.202-207
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• 2010

We investigated the electrochemical properties for Langmuir-Blodgett(LB) films mixed with l-bromotetradecane(Cl4), l-bromohexadecane(Cl6), and l-bromooctadecane(Cl8). The alkyl bromides mixture was deposited by using the Langmuir-Blodgett method on the 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(0.5, 1.0, 1.5 and 2.0 N) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350 m V, continuously oxidized to 1650 mV. The scan rate was 100 mV/s. As a result, LB films of Cl4, Cl6, and Cl8 mixture monolayers appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of alkyl bromides amount.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.8
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• pp.724-731
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• 2006

We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with 4-octyl-4'-(5-carboxylpentamethyleneoxy)azobenzene (denoted as 8A5H) and phospholipid(L-a-dimyristoylphosphatidylcholine, denoted as DMPC and L-a-dilauroylphosphayidylcholine, denoted as DLPC). The LB films of 8A5H, 8A5H-DMPC and 8A5H-DLPC mixture monolayers were deposited by using the LB 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 1.0 mol/L) of $NaClO_4$ solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rates were 50, 100, 150 and 200 mV/s, respectively. As a result, LB films of 8A5H and 8A5H-DLPC mixture monolayers appeared irreversible process caused by only the oxidation current from the cyclic voltammogram and LB films of 8A5H-DMPC monolayer mixture was found to be caused by a reversible oxidation-reduction process.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.3-5
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• 1993

The use of preformed polymers and their cross-linking have been attempted in order to improve the intrinsic fragility of monolayers and Langmuir-Blodgett (LB) films and to make their technological applications possible. It has shown that an imidization followed a polyion-complexation can stabilize the LB films against heat and solvents. And, when the polymer structure was property designed, concurrent removal of the alkyl tails together with imide formation could be accomplished. In this paper, we present a characteristic monolayer behavior of polymer with pendent polyethers and carboxyls, it's polyion-complexed LB film with subphase polymer PAA, and a possible skeletonization of the LB film by thermal imidization. Also, deposition status of LB films are evaluated by using QCM.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.537-539
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• 1993

The use of preformed polymers and their cross-linking have been attempted in order to improve the intrinsic fragility of monolayers and Langmuir-Blodgett(LB) films and to make their technological applications possible. It has shown that an imidization followed a polyion-complexation can stabilize the LB films against heat and solvents. And, when the polymer structure was properly designed, concurrent removal of the alkyl tails together with imide formation could be accomplished. In this paper, we present a characteristic monolayer behavior of polymer with pendent polyethers and carboxyls, it's polyion-complexed LB film with subphase polymer PAA, and a possible skeletonization of the LB film by thermal imidization. Also, deposition status of LB films are evaluated by using QCM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.43-46
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• 2002

We have investgated the photoisomerization using light irradiation 8A5H-phospholipid( L-$\alpha$-dimyristoylphosphatidylcholine[DMPC], L-$\alpha$-dilauroylphosphatidylcholine[DLPC]mixture LB film accumulated by monolayer on an ITO. We determined electrochemical measurement 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 measured in $NaClO_{4}$ solution at a variable concentration and variable number layers LB film. The scan rate was 100mV/s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.342-345
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• 1997

We fabricated the sample of u1tra thin lipid membrane(L-${\alpha}$-DLPC ) by LB methode. The $\pi$-A isotherm of the DLPC was measured at the air-water interface varying with the compressing speed and amounts of solutions for spreading. For good property of lipid monolayer film, it was necessary for the lower speed of compressing, and 40${\mu}\ell$ of solutions for spreading. The molecular arrangement of deposited films were evaluated by measuring the absorption, transmitance and intensity with the UV spectrophotometer. The Y-type multilayers prepared at 50mN/m showed weaker than Z-type. So we found building-up of structurally high quality LB films is essential to study properties of the films and to get reproducible data.