• Electrical & Electronic Materials
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• v.9 no.7
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• pp.674-679
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• 1996

Using the home made Kuhn type LB (Langmuir - Blodgett) film's deposition apparatus, We measured the displacement current of monolayer film on the water surface. The obtained displacement current had each different pattern by the kind of solution while varying pressure of the monolayer. Solution of 4 - octyl - 4' - (5 - carboxyl - pentamethyleneoxy ) - azobenzene (8A5H) and stearic acid (CH$_{3}$(CH$_{2}$)$_{16}$COOH) (C18) were spreaded at the air water interface respectively, and the current induced by the dynamic behavior of molecules were pressed by barrier. Displacement current of 8A5H measured small current than C18 at same condition and it was positive direction when increasing pressure but it was negative direction when decreasing pressure. Also, Two patterns of displacement current were symmetrical form and appeared repeatedly. The C18 has unsymmetrical form of displacement current and weak current when decreasing pressure (expansion). The C18 molecules have two distinct peak values of displacement current that show that the orientations of molecules were changed largely at this points. From these results, we obtained that the 8A5H has more elasticity than the C18.8.C18.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.64-73
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• 2010

This study was conducted to modify the surface properties of papers by formation of hydrophobic self-assembled monolayer(SAM) on paper surface with silanes. A base paper I(0.5% AKD) and base paper II(1.0-1.5% AKD) were reacted with silanes(PFDTES, DMDCS, MODDCS) by immersion method and vapor deposition method. Hydrophobic SAMs(contact angle value>$120^{\circ}C$) were obtained on all papers after treatment with $10^{\mu}l$ PFDTES for 15min, with $50^{\mu}l$ DMDCS for 30min, with $50^{\mu}l$ MODDCS for 300min. When applying PFDTES to paper surface, lower silane concentration and shorter reaction time were required, whereas MODDCS with long alkyl chain required the longest reaction time of 300min. The st$\ddot{o}$ckight sizing degree of silane treated papers were increased between 105sec(base paper I) and 130sec(base paper II). The wet tensile strength of PFDTES-treated base papers(I, II) increased by 10-34% after SAM formation. However, the wet tensile strength of the DMDCS-treated base paper(I) was found to decrease from 0.067kN/m to 0.038kN/m; this may due to the cellulose degrading as a result of generated hydrogen chloride when hydroxyl group of cellulose were reacted with DMDCS. No apparent changes of PPS roughness on silane-treated papers are observed. The ATR-IR spectrum showed absorption peak located at 465 and 1200cm-1 which can be assigned to the Si-O-C asymmetric stretching and Si-O-C bonds, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.3
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• pp.105-110
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• 2002

J-aggregates in the mutual mixing LB films of [6Me-DS]$_{1-x}$ [DO]$_{x}$,[DS]$_{1-x}$ [DO]$_{x}$ and [DSe]$_{1-x}$ [DO]$_{x}$ have been studied by optical absorption, fluorescence and surface pressure-area isotherms. In [6Me-DS]$_{1-x}$ [DO]$_{x}$ films, sharp J-band absorption and fluorescence of [6Me-DS] are linearly shifted to the longer wavelength for the replacement of [6Me-DS] by [DO]. According to the x, a smooth shift of the limited area has been cleared. In the [DS]-[DO] system, the J-band is enhanced at 1:1 composition and strong fluorescence is also observed. Also, the presence of phase separation was suggested in the [DSe]-[DO] system, because the absorption spectra were decomposed into [DSe] and [DO] spectra. On the other hand, in the pressure-area isothermal study, reduction in the molecular occupying area of monolayers has been clarified. This could be ascribed to the enhancement of molecular ordering in J-aggregates. These facts are also believed to reflect the most closely packed arrangement of chromophores in the merocyanine dye monolayers. Thus, it was confirmed that the interaction between mixed dye molecules and the CdC1$_2$+KHCO$_3$subphases affected the J-aggregates of the LB films. Also. it is thought that the J-aggregates are formed non-dimensionally in LB films, such as solution synthesized [DX:DO] assemblies on mixing.s on mixing.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.143-152
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• 2002

The growth of Polypyrrole film has been investigated during electropolymerization in an aqueous solution on bare and SAM modified gold electrodes by in-situ EQCM and ex-situ AFM. According to the result of cyclic voltammetry measurements, in the case of a bare gold electrode, the electrochemical deposition of polypyrrole were dependent on the limiting oxidative potential, but not on scan numbers. When the limiting potential higher than 0.8 V was applied on the electrode, the amount of polypyrrole deposited on a gold electrode was rapidly increased and the abnormal mass change attributed to the rearrangement of polypyrrole films was observed as the scan number increased. The polypyrrole film Prepared on electrodes modified with 1-dodecanethiol SAM or thiophene SAM grew 3-dimensionally with the rearrangement of film. However, in the case of BPUS SAM, 2-dimensional layer-by-layer growth of film was observed without the rearrangement of film. AFM images showed films with chain-shaped and/ or donut-shaped polymers when grown rapidly and a wrinkled film at the steady state condition.

• Polymer(Korea)
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• v.24 no.1
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• pp.90-96
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• 2000

Organic electroluminescent (EL) device was fabricated with Alq$_3$ as an emitting material and PDPMA ultra thin film prepared by Langmuir-Boldgett technique as a polymer hole transport layer. A stable condensed PDPMA monolayer was obtained using arachidic acid as a surface active material. The thickness and absorbance of PDPMA LB film increased line-arly with the layer numbers. The organic multilayered device consisted of ITO/PDPMA LB film (19 layers)/Alq$_3$/Al emitted green light with brightness of 2500 cd/m$^2$ at a DC 14 V Especially, the drive voltage of EL device having PDPMA LB film of 15 layers exhibited the value as low as 4 V. The effects of thickness control and molecular orientation in the PDPMA LB film on EL performance were discussed.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1320-1322
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• 1994

Photoisomerization characteristics of 4-octyl-4'-(5-carboxy-pentamethyleneoxy) azobenzene molecules (8A5H) were attained by measurement of absorbtion spectra. 8A5H in chroloform($6.0{\times}10^{-5}[M/l]$) shows trans to cis and cis to trans isomerization by irradiation of lights of 360[nm] and 450[nm] wavelength. From LB monolayer films of 8A5H, also the cis/trans photoisomerization was obtained and it has reversibility and memory characteristics. We are now trying to detect these properties of 8A5H electrically. On this paper, we investigated the structural changes of monolayer on the water surface by measuring the displacement current as a preliminary experiment. The measuring system was constructed at home-made Kuhn type LB(Langmuir-Blodgett) deposition apparatus. 8A5H solution was spreaded at the air-water interface and the currents induced by the dynamic behavior of molecules were measured when the molecules were pressed by barrier. The reversibility of displacement currents by compression and expansion was obtained from 8A5H molecules, which shows the compressed molecules have a tendency to disperse after the compression. From this experiment, we conclude that the behavior of molecules on water surface can be monitored electrically by using this current measuring method, and this method can also be applied to detect the photoisomerization of monolayers on water surface.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1699-1701
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• 2000

The dynamic behavior of fatty acid monolayers at the air-water interface was investigated using a displacement current-measuring technique coupled with the so-called Langmuir film technique and also the dipole moment of the acids was determined. The displacement current flowing though a short circuit wan generated only when induced charges on an electrode flowing though suspended in air was changed by monolayer compression. The displacement current measurement was found to be a very sensitive method used for a better understanding of the relationship between the structure and function of the monolayers placed on the water surface and it was also found to be a very useful method for detecting the dynamic motion of molecules in the entire range from the so-called gaseous state to solid state at the same time. In the paper investigate fatty monolayer dynamic state and electric property character. As result. Displacement current generate higher nearly distance electrodel and water surface. Also, Molecule behavior was found pocess active higher thermal.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.642-647
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• 1993

Monolayers of pure surfactant squaraine, DSSQ(4-distearyl amino phenyl-4'-dimethylaminophenylsquaraine), were deposited on $SnO_2 $ electrodes by the Langmuir-Blodgett film technique. The DSSQ film exhibits ${\lambda}_{max}$ at ∼530 nm. The absorption is significantly red-shifted from the solution of DSSQ (633 nm in chloroform), suggesting that the squaraine chromophores form aggregates in the LB film. The photogeneration of the squaraine aggregates is studied by measuring the photocurrents in photoelectrochemical cells consisting of the squaraine of the aggregates is found to parallel its absorption spectrum and quantum efficiency as high as 0.3% has been observed. While the photocurrent was attenuated exponentially when stearic acid layers (up to 8 layers) are inserted between the squaraine layer and the electrode, it is nearly extinguished when the squaraine layer is over-coated with 2 layers of stearic acid. A model for the observation is proposed and the roles of the electrolytes and oxygen on the photogeneration process will be discussed.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.2
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• pp.13-20
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• 2023

The process of microelectromechanical system (MEMS) fabrication involves surface treatment to impart functionality to the device. Such surface treatment method is the self-assembled monolayer (SAM) technique, which modifies and functionalizes the surface of MEMS components with organic molecule monolayer, possessing a precisely controllable strength that depends on immersion time and solution concentration. These monolayers spontaneously adsorb on polymeric substrates or metal/ceramic components offering high precision at the nanoscale and modifying surface properties. SAM technology has been utilized in various fields, such as tribological property control, mass-production lithography, and ultrasensitive organic/biomolecular sensor applications. This paper provides an overview of the development and application of SAM technology in various fields.

• Korean Journal of Optics and Photonics
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• v.34 no.6
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• pp.283-288
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• 2023

We investigate the optical and electrical properties of silver nanofilms deposited on transparent substrates such as quartz, sapphire, and slide glass treated with (3-mercaptopropyl) trimethoxysilane (MPTMS). The effect of MPTMS treatment on physical properties is studied through scanning electron microscope (SEM) images, UV-visible transmission, and current-voltage measurements. The SEM images show morphology change of the silver nanofilm, and the UV-visible transmission spectra reveal that the localized surface-plasmon resonance effect is reduced due to the morphology change. These results imply that the uniformity of silver nanofilm is improved by MPTMS treatment for various transparent substrates, resulting in a 100-fold decrease in the electrical resistance of the silver nanofilm.