Study of the stability of self-assembled N-vinylcarbazole monolayers to protect copper against corrosion

N-Vinylcarbazole (NVC) monolayers were self-assembled on copper surfaces. The electrochemical properties of the copper surfaces modified by NVC self-assembled monolayers (SAMs) were investigated using polarization and electrochemical impedance spectroscopic (EIS) methods. The polarization measurements indicated that the NVCSAMs could reduce the rates of the anodic and cathodic reaction on the surface of copper electrodes in 0.5 mol dm-3 NaCl solution. The EIS results showed the NVC formed a closely packed film that was able to inhibit copper corrosion. X-Ray photoelectron spectroscopy (XPS) analysis of the copper samples and atomic adsorption analysis of the solution showed that the copper surfaces were covered by NVCSAMs, and the adsorption of NVC on the copper surfaces was accompanied with dissolution of Cu into the solution.

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An impedance investigation of corrosion protection of copper by self-assembled monolayers of alkanethiols in aqueous solution

Journal of the Serbian Chemical Society ◽

10.2298/jsc0410791l ◽

2004 ◽

Vol 69 (10) ◽

pp. 791-805 ◽

Cited By ~ 35

Author(s):

Guiyan Li ◽

Houyi Ma ◽

Yongli Jiao ◽

Shrnhao Chen

Keyword(s):

Equivalent Circuit ◽

Corrosion Protection ◽

Electrochemical Impedance ◽

Copper Substrate ◽

Self Assembled Monolayers ◽

Copper Surfaces ◽

Hydrophobic Barrier ◽

Assembled Monolayers ◽

Covered Electrodes ◽

Self Assembled

Self-assembled monolayers (SAMs) of three n-alkanethiols, 1-octadecanethiol (C18SH), 1-dodecanethiol (C12SH), and 1-hexanethiol (C6SH), were formed on fresh, oxide- free copper surfaces obtained by HNO3 etching. The corrosion protection abilities of the three alkanethiol SAM s were evaluated in 0.2 mol cm-3 NaCl, 0.2 mol cm-3 HCl and 0.2 mol dm?3 H2SO4 solutions using the electrochemical impedance spectroscopy (EIS) method. The SAMs act as a hydrophobic barrier layer, which effectively prevents the copper substrate from contacting corrosive ions, thereby inhibiting corrosion of the copper to a considerable degree. A general equivalent circuit for the SAM-covered electrodes was proposed, bymeans of which the impedance behavior of the electrodes was interpreted and the corresponding electrochemical parameters were acquired. In addition, the quality of the SAMs and development of defects in the SAMs were also been evaluated based on the equivalent circuit. The dependence of the capacitance of the SAMs on the applied potentials was used to determine the stability of the SAMs at the applied potentials.

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Investigation of two-component mixed self-assembled monolayers on gold

Canadian Journal of Chemistry ◽

10.1139/v01-022 ◽

2001 ◽

Vol 79 (3) ◽

pp. 328-336

Author(s):

Zhen Wang ◽

Yan-Li Shi ◽

Hu-Lin Li

Keyword(s):

Photoelectron Spectroscopy ◽

Self Assembly ◽

Electrochemical Impedance ◽

Impedance Analysis ◽

Self Assembled Monolayers ◽

X Ray ◽

Molar Ratios ◽

Two Component ◽

Assembled Monolayers ◽

Self Assembled

Two-component mixed self-assembled monolayers (SAMs) composed of 2-mercapto-5-methyl-1,3,4-oxadiazole (MMO) and 1-dodecanethiol (C12SH) in various molar percentages were prepared on gold surfaces by self-assembly. X-ray photoelectron spectroscopy (XPS) and wettability results gave evidence that the coverage of MMO was controlled by the composition of MMO in the assembling solution. The monolayer coverage and apparent rate constant of the redox active probes in solution of different molar ratios of mixed SAMs could be calculated using impedance measurements. The cyclic voltammetry reveals that the probes are selectively passed through the mixed SAMs depending upon their properties.Key words: self-assembled monolayers (SAMs), X-ray photoelectron spectroscopy (XPS), electrochemistry, electrochemical impedance analysis.

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Microfluidic Impedance Biosensor Chips Using Sensing Layers Based on DNA-Based Self-Assembled Monolayers for Label-Free Detection of Proteins

Biosensors ◽

10.3390/bios11030080 ◽

2021 ◽

Vol 11 (3) ◽

pp. 80

Author(s):

Khaled Alsabbagh ◽

Tim Hornung ◽

Achim Voigt ◽

Sahba Sadir ◽

Taleieh Rajabi ◽

...

Keyword(s):

Troponin I ◽

Electrochemical Impedance ◽

Specific Binding ◽

Self Assembled Monolayers ◽

Significant Shift ◽

Label Free ◽

Label Free Detection ◽

Assembled Monolayers ◽

Self Assembled ◽

Biosensor Chip

A microfluidic chip for electrochemical impedance spectroscopy (EIS) is presented as bio-sensor for label-free detection of proteins by using the example of cardiac troponin I. Troponin I is one of the most specific diagnostic serum biomarkers for myocardial infarction. The microfluidic impedance biosensor chip presented here consists of a microscope glass slide serving as base plate, sputtered electrodes, and a polydimethylsiloxane (PDMS) microchannel. Electrode functionalization protocols were developed considering a possible charge transfer through the sensing layer, in addition to analyte-specific binding by corresponding antibodies and reduction of nonspecific protein adsorption to prevent false-positive signals. Reagents tested for self-assembled monolayers (SAMs) on gold electrodes included thiolated hydrocarbons and thiolated oligonucleotides, where SAMs based on the latter showed a better performance. The corresponding antibody was covalently coupled on the SAM using carbodiimide chemistry. Sampling and measurement took only a few minutes. Application of a human serum albumin (HSA) sample, 1000 ng/mL, led to negligible impedance changes, while application of a troponin I sample, 1 ng/mL, led to a significant shift in the Nyquist plot. The results are promising regarding specific detection of clinically relevant concentrations of biomarkers, such as cardiac markers, with the newly developed microfluidic impedance biosensor chip.

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Mixed self-assembled monolayers of terminally functionalized thiols at gold surfaces characterized by angle resolved X-ray photoelectron spectroscopy (ARXPS) studies

Fresenius Journal of Analytical Chemistry ◽

10.1007/s002160051487 ◽

1999 ◽

Vol 365 (1-3) ◽

pp. 272-276 ◽

Cited By ~ 18

Author(s):

J. Heeg ◽

U. Schubert ◽

F. Küchenmeister

Keyword(s):

Photoelectron Spectroscopy ◽

Self Assembled Monolayers ◽

Gold Surfaces ◽

X Ray ◽

Assembled Monolayers ◽

Self Assembled

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X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.3.2 ◽

2012 ◽

Vol 3 ◽

pp. 12-24 ◽

Cited By ~ 13

Author(s):

Hicham Hamoudi ◽

Ping Kao ◽

Alexei Nefedov ◽

David L Allara ◽

Michael Zharnikov

Keyword(s):

Chain Length ◽

Photoelectron Spectroscopy ◽

Self Assembled Monolayers ◽

Phenylene Ethynylene ◽

X Ray ◽

Molecular Length ◽

Assembled Monolayers ◽

Self Assembled ◽

Gold Thiolate

Self-assembled monolayers (SAMs) of nitrile-substituted oligo(phenylene ethynylene) thiols (NC-OPEn) with a variable chain length n (n ranging from one to three structural units) on Au(111) were studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and near-edge absorption fine-structure spectroscopy. The experimental data suggest that the NC-OPEn molecules form well-defined SAMs on Au(111), with all the molecules bound to the substrate through the gold–thiolate anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36° for all the target systems. In contrast, the average twist of the OPEn backbone (planar conformation) was found to depend on the molecular length, being close to 45° for the films comprising the short OPE chains and ~53.5° for the long chains. Analysis of the data suggests that the attachment of the nitrile moiety, which served as a spectroscopic marker group, to the OPEn backbone did not significantly affect the molecular orientation in the SAMs.

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Interfacial Adhesion of Cu to Self-Assembled Monolayers on SiO2

MRS Proceedings ◽

10.1557/proc-695-l7.7.1 ◽

2001 ◽

Vol 695 ◽

Author(s):

G. Cui ◽

M. Lane ◽

K. Vijayamohanan ◽

G. Ramanath

Keyword(s):

Binding Energy ◽

Photoelectron Spectroscopy ◽

Interfacial Adhesion ◽

Adhesion Energy ◽

Binding Energies ◽

Self Assembled Monolayers ◽

Chemical Binding ◽

Barrier Materials ◽

Assembled Monolayers ◽

Self Assembled

ABSTRACTAs the critical feature size in microelectronic devices continues to decrease below 100 nm, new barrier materials of > 5 nm thickness are required. Recently we have shown that self-assembled monolayers (SAMs) are attractive candidates that inhibit Cu diffusion into SiO2. For SAMs to be used as barriers in real applications, however, they must also promote adhesion at the Cu/dielectric interfaces. Here, we report preliminary quantitative measurements of interfacial adhesion energy and chemical binding energy of Cu/SiO2 interfaces treated with nitrogen-terminated SAMs. Amine-containing SAMs show a ~10% higher adhesion energy with Cu, while interfaces with Cu-pyridine bonds actually show degraded adhesion, when compared with that of the reference Cu/SiN interface. However, X-ray photoelectron spectroscopy (XPS) measurements show that Cu-pyridine and Cu-amine interactions have a factor-of-four higher binding energy than that of Cu-N bonds at Cu/SiN interfaces. The lack of correlation between adhesion and chemical binding energies is most likely due to incomplete coverage of SAMs.

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Formation and stability of porphyrin and phthalocyanine self-assembled monolayers on ZnO surfaces

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424616501029 ◽

2016 ◽

Vol 20 (08n11) ◽

pp. 1264-1271 ◽

Cited By ~ 3

Author(s):

Hanna Hakola ◽

Essi Sariola-Leikas ◽

Paavo Jäntti ◽

Thomas Mokus ◽

Kati Stranius ◽

...

Keyword(s):

Thin Films ◽

Zno Nanorods ◽

Self Assembled Monolayers ◽

Layer Formation ◽

Zno Film ◽

Assembled Monolayers ◽

Self Assembled ◽

Anchoring Groups ◽

The Stability ◽

Phosphate Groups

Formation of self-assembled monolayers (SAMs) of three porphyrin and one phthalocyanine derivatives on thin ZnO film was studied by monitoring absorption spectra of the samples. The compounds were equipped with carboxylic or phosphate groups to bind to the surface. The SAM formation was found to be fast. The layer was formed in less than 15 min for all studied porphyrins, and 30 min was sufficient to form phthalocyanine layer. For porphyrins with different anchor groups the SAM formation was too fast to see any difference between the anchoring groups. The stability of SAMs was tested then by immersing the samples into neat solvents. Upon immersion the SAMs were gradually losing the absorbance for all the compounds with degradation trends being in line with p[Formula: see text] values of the binding groups of the same type. However, even for the weakest binding group the SAM was relatively stable after a few tens of minutes of washing, which was sufficient to remove physisorbed compounds but the SAM was essentially not destroyed. Comparison of SAMs on thin films with SAMs on ZnO nanorods and TiO2 nanoparticle films indicated the same fast layer formation but relatively weaker SAMs stability, showing 20–40% faster absorption losses during the washing.

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