• Title/Summary/Keyword: Self Assembled Monolayers

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Self-Assembled Monolayers(SAMs) (자기조립 단분자막)

  • 박경선;이보현;성명모
    • Polymer Science and Technology
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    • v.15 no.3
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    • pp.286-295
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    • 2004
  • 자기조립 단분자막 (self-assembled monolayers, SAMs)은 주어진 기질의 표면에 자발적으로 입혀진 규칙적으로 잘 정렬된 유기 분자막이다 (그림 1). SAMs의 제조에 이용되는 계면 활성제 분자는 그림 2에서 보여주듯이 세 개의 부분으로 이루어져 있다. 먼저 기질과 결합하는 머리 부분의 반응기, 규칙적인 분자 막 형성을 가능하게 하는 몸통 부분의 긴 알칸사슬, 그리고 분자 막의 기능을 좌우하는 꼬리 부분의 작용기로 나누어진다. 가장 간단한 작용기로는 알킬 그룹이 있으나 분자 막에 특수한 기능을 부여하기 위해서는 여러 가지 다른 그룹들 (예:NH$_2$, OH, COOH 등)이 이용되고 있다. (중략)

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Nano-identification for the Cleavage of Disulfide Bond during the Self-Assembly Processes of Unsymmetric Dialkyl Disulfides on Au(111)

  • Noh, Jae-Geun
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.553-557
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    • 2005
  • The formation of striped phases of unsymmetric hexyl octadecyl disulfide ($CH_3(CH_2)_5SS(CH_2)_{17}CH_3$, HOD) and 1-hydroxyundecyl octadecyl disulfide ($CH_3(CH_2)_{17}SS(CH_2)_{11}$OH, HUOD) on Au(111) and graphite has been investigated by scanning tunneling microscopy (STM) to understand the self-assembly processes of dialkyl disulfides. STM imaging clearly shows the formation of striped phases having corrugation periodicities that are nearly consistent with the molecular length of alkanethiolate moieties formed after the S-S bond cleavage of dialkyl disulfide on a gold surface. On the other hand, self-assembled monolayers (SAMs) of dialkyl disulfides on a graphite surface displayed long-range, well-ordered monolayers with one striped pattern that shows periodicity as a function of molecular length via nondissociative adsorption. From a nonoscopic viewpoint, we have clearly demonstrated that dialkyl disulfide SAMs on gold form via S-S bond cleavage of disulfide.

Study on Electrochemical Property of Self-Assembled Viologen Monolayers Using Electrochemical Quartz Crystal Microbalance (EQCM) Method (EQCM법을 이용한 자기조립된 Viologen 단분자막의 전기화학적 특성 연구)

  • Lee, Dong-Yun;Park, Sang-Hyun;Park, Jae-Chul;Kwon, Young-Soo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.3
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    • pp.107-110
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    • 2006
  • We fabricated the monolayers onto QCM by self-assembly using viologen, which has been widely used as electron acceptor. A gold electrode of the QCM was cleaned by piranha solution and prepared the ethanol-acetonitrile(1:1) solution with 2 m mol/l viololgen compounding of pure hi gas. We determined the time dependence to resonant frequency shift during self-assembly process and the electrochemical behavior of the self-assembled viologen monolayers by cyclic voltammetry. With increasing scan rate, the redox peak current of the viologen increased linearly. This was signified that the redox reaction was reversible. The EQCM measurements revealed the anions transfer during redox reactions, respectively. From the EQCM data, the well-defined shape peaks were nearly equal charges by cyclic voltammetry.

A Study on the Current-Voltage Characteristics of Self-Assembled Organic Molecules by using STM

  • Kim Seung-Un;Shin Hoon-Kyu;Kwon Young-Soo
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.3
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    • pp.115-118
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    • 2005
  • Currently, molecular devices are reported utilizing active self-assembled monolayers (SAMs) containing the nitro group as the active component, which has active redox centers [1]. SAMs are ordered molecular structures formed by the adsorption of an active surfactant on a solid surface. The molecules will be spontaneously oriented toward the substrate surface and form an energetically favorable ordered layer. During this process, the surface-active head group of the molecule chemically reacts with and chemisorbs onto the substrate In this paper, the electrical properties of the 4'4- di(ethynylphenyl)-2'-nitro-1-benzenethiolate was confirmed. This material is well known as a conducting molecule having possible application to molecular level negative differential resistance (NDR) device. To deposit the self-assembly monolayers onto the gold electrode, the prefabricated Au(1 l l) substrates were immersed into 0.5[mM/l] self-assembly molecule in THF solution. Then, the electrical properties and surface morphologies of 4' 4-di(ethynylphenyl)-2' -nitro-1-benzenethiolate were measured by using the ultra-high vacuum scanning tunneling microscopy (UHV-STM).

Electrical Characteristics of Self-Assembled Organic Thin Films Using Ultra-High Vacuum Scanning Tunneling Microscopy (UHV STM을 이용한 유기 초박막의 전기적 특성 연구)

  • Kim, Seung-Un;Shin, Hoon-Kyu;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.108-111
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    • 2003
  • Currently, molecular devices are reported utilizing active self-assembled monolayers containing the nitro group as the active component, which has active redox centers[1]. We confirm the electrical properties of 4,4-di(ethynylphenyl)-2'-nitro-1-benzenethiolate. To deposit the SAM layer onto gold electrode, we transfer the prefabricated Au(111) substrates into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured current-voltage curve using ultra high vacuum scanning tunneling microscopy (UHV STM), I-V curve also clearly shows several current peaks between the negative bias region (-0.3958V) and the positive bias region (0.4658V), respectively.

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Study on Morphology Investigation and Electron-Transfer Property of Self-Assembled Viologen Monolayers (자기조립된 Viologen 단분자막의 모폴로지 관찰과 전하이동 특성 연구)

  • Lee, Dong-Yun;Park, Sang-Hyun;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.395-396
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    • 2005
  • We fabricated self-assembled monolayers(SAMs) onto quartz crystal microbalance(QCM) using viologen, which has been widely used as electron acceptor and electron transfer mediator. We determined the time dependence to resonant frequency shift during self-assembly process and observed the morphology of self-assembled mono layers by STM and investigated the electrochemical behavior of SAMs by cyclic voltammetry. Electrochemical deposition of viologen was investigated using electrochemical quartz crystal microbalance(EQCM). The redox reactions of viologen were highly reversible and the EQCM has been employed to monitor the electrochemically induced adsorption of SAMs during the redox reactions.

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Vertical Alignment of Liquid Crystals by Ordering Effect of Self-assembled Monolayers on the Ion-beam-irradiated Anisotropic Surface

  • Park, Ji-Sub;Seok, Keun-Yeong;Hwang, Soo-Won;Kim, Jae-Chang;Yoon, Tae-Hoon;Kim, Jae-Hoon;Kim, Hak-Rin
    • Journal of Information Display
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    • v.11 no.4
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    • pp.144-148
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    • 2010
  • In this paper, vertically aligned (VA) liquid crystal (LC) modes were investigated using the alkyl chain ordering effect of self-assembled monolayers (SAMs) prepared on the anisotropic inorganic surface. On the anisotropic surface prepared through oblique ion beam irradiations, the SAM molecules are adsorbed, producing macroscopic alkyl chain ordering, which can determine the pretilt direction of the vertically aligned LC molecules through the intermolecular interactions on the surface.