• 제목/요약/키워드: Self Assembled Monolayers

검색결과 221건 처리시간 0.022초

Self-Assembled Monolayers of Alkanethiols on Clean Copper Surfaces

  • ;김연수
    • Bulletin of the Korean Chemical Society
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    • 제22권7호
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    • pp.748-752
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    • 2001
  • Alkanethiols (CH3(CH2)n-1SH) based self-assembled monolayers (SAMs) on the clean copper surfaces have been examined for n = 4, 8, and 16. Using X-ray photoelectron spectroscopy (XPS) and contact angle analysis, it is found that alkanethiolate monolayers similar to those on gold are formed on clean copper surfaces. The monolayers are stable in air up to about 140 $^{\circ}C.$ Above 160 $^{\circ}C$ the monolayers begin to desorb through the oxidation reaction of the thiolate to sulfonate, with the alkyl chains remaining intact. Following this desorption step, the copper surface has begun to oxidize to CuO at about 180 $^{\circ}C$.

자기조립된 Viologen 단분자막의 표면이미지 관찰과 계면전하이동 특성 연구 (Study on Morphology Investigation and Charge-transfer Property of Self-assembled Viologen Monolayers)

  • 박상현;이동윤;박재철;권영수
    • 한국전기전자재료학회논문지
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    • 제19권3호
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    • pp.246-249
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    • 2006
  • 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 on resonant frequency shift during self-assembly process and observed the morphology of self-assembled monolayers 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 redok reactions. The total frequency change was about 9.5 Hz, and 7.1 Hz. From the data, we could know the mass change was about 10.16 ng and 7.60 ng, respectively. Finally, the EQCM has been employed to monitor the electrochemically induced adsorption of self-assembled monolayers on Au surfaces.

Self-Assembled and Langmuir-Blodgett Arachidic Acid Monolayers on Silver: A Comparative Reflection-Absorption Fourier Transform Infrared Spectroscopic Study

  • Ahn, Sang-Jung;Mirzakhojaev, Diyas A.;Son, Dong-Hee;Kim, Kwan
    • Bulletin of the Korean Chemical Society
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    • 제15권5호
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    • pp.369-374
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    • 1994
  • Self-assembled (SA) and Langmuir-Blodgett (LB) monolayers of arachidic acid on silver surfaces have been investigated by a reflection-absorption Fourier transform infrared spectroscopy. Arachidic acid was adsorbed on silver as carboxylate with its two oxygen atoms bound symmetrically to the surface. Although both the SA and LB monolayers consisted of fully extended trans zigzag carbon chains, a closer examination indicated that the SA monotayers should possess a more ordered crystalline structure than the LB monolayers. The infrared spectral data dictated that the extent of methyl group exposure at the air-film interface was greater in the SA monolayers than the LB monolayers, in agreement with the contact angle measurement. From a theoretical analysis, the alkyl chains in each monolayers seemed to be tilted away from the surface normal by less than $3.5^{\circ}$, but in opposite directions. Arachidic acid monolayers were concluded to have same structure as stearic acid monolayers.

Electrochemical Characterization of Nanosized Electrode Arrays Prepared from Nanoporous Self-Assembled Monolayers

  • Choi, Shin-Jung;Park, Su-Moon
    • Bulletin of the Korean Chemical Society
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    • 제23권5호
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    • pp.699-704
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    • 2002
  • We characterized nanoelectrode arrays prepared from self-assembled monolayers (SAMs) by adsorption from a solution containing thiolated $\beta$-cyclodextrin ($\beta$-CD) and n-alkanethiol on the gold electrode surface, using electrochemical methods. While the framework, the n-hexadecanethiol SAM, effectively blocked electron transfer between the electrode surface and solution-phase redox probe molecules, the $\beta$-CD cavities isolated in the forests of n-hexadecanethiol molecules were shown to act as an ultramicroelectrode array. The shapes of cyclic voltammograms of probe molecules were related to the number densities of $\beta$-CD molecules within the monolayer films. Probe molecules that have the correct combination of physical and chemical characteristics were shown to effectively penetrate the framework through the $\beta$-CD pores and exchange electrons with the electrode surface.

도파민으로 수식된 SAMs 전극에서 NADH의 전기촉매에 의한 산화 (Electrocatalytic Oxidation of NADH at Electrodes of Self-assembled Monolayers Modified with Dopamine)

  • 차성극
    • 대한화학회지
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    • 제48권2호
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    • pp.151-155
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    • 2004
  • 금 전극 표면을 시스테인으로 수식한 자기조립 단층막(self-assembled monolayers; SAMs)을 만들고 이를 퀴논 작용기를 갖고 있는 도파민과 반응시킨 수식전극을 제작하였다. 이 전극을 에탄올 내에서 6시간 정도 정치하면 SAMs가 잘 정돈 되어서 보다 개선된 형태의 순환전압전류법(cyclic voltammetry; CV)의 결과를 얻게 되었다. 그 결과 SAMs 말단에 o-퀴논의 산화-환원특성은 0.1 M 인산염 완충용액(pH=7.10)에서 형식전위 값이 0.28 V이고 피크 전위차이가 없는 가역성이 뛰어난 전극이 제작되었다. 이 전극으로 NADH의 정량을 위한 검정선을 제작하였으며, 5.0 ${\times}\;10^{-4}$ M농도까지 정량이 가능한 0.993의 뛰어난 상관관계를 보였다.