Alkanethiol Monolayers on Preoxidized Gold. Encapsulation of Gold Oxide under an Organic Monolayer

Ron, Hannoch; Rubinstein, Israel

doi:10.1021/la00024a030

Cited by 176 publications

(180 citation statements)

References 4 publications

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“…1, the Au 4f 7/2 bands with binding energies of 84.85 and 83.95 eV correspond to oxidized and reduced gold surfaces, respectively, which indicate that the ethanol treatment changed the gold surface from the oxidized to the reduced state. The narrow scans in the Au 4f region of oxidized gold surface shifted to higher binding energy compared with the reduced surface 36,41,42 , indicating a remarkable energy difference between each doublet.…”

Section: Resultsmentioning

confidence: 96%

“…Proper cleaning of the gold surface is necessary to obtain high-quality thiol-gold-based SAM. For this purpose, rational methods for preparing highly reproducible gold surfaces, including the oxidative [35][36][37][38] and reductive 36,37 pretreatments, have been proposed. Briefly, gold substrates could be oxidized to a positive charge state via conventional methods, such as ultraviolet/ozone, oxygen plasma, electrochemical oxidation and piranha solution oxidation.…”

Section: Resultsmentioning

confidence: 99%

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Quantifying thiol–gold interactions towards the efficient strength control

et al. 2014

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The strength of the thiol-gold interactions provides the basis to fabricate robust self-assembled monolayers for diverse applications. Investigation on the stability of thiol-gold interactions has thus become a hot topic. Here we use atomic force microscopy to quantify the stability of individual thiol-gold contacts formed both by isolated single thiols and in self-assembled monolayers on gold surface. Our results show that the oxidized gold surface can enhance greatly the stability of gold-thiol contacts. In addition, the shift of binding modes from a coordinate bond to a covalent bond with the change in environmental pH and interaction time has been observed experimentally. Furthermore, isolated thiol-gold contact is found to be more stable than that in self-assembled monolayers. Our findings revealed mechanisms to control the strength of thiol-gold contacts and will help guide the design of thiol-gold contacts for a variety of practical applications.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Quantifying thiol–gold interactions towards the efficient strength control

et al. 2014

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“…32,33 The thickness of these oxide layers was typically on the order of ∼1 nm, depending upon the plasma exposure time. 34 The 3DAPT can be used to reveal the surface composition and thickness of an oxide coating on gold. In addition, mass spectral analysis can be expected to provide useful information to identify the film composition.…”

Section: Resultsmentioning

confidence: 99%

“…The measured thickness of the oxide layer is relatively thick at 8-10 nm when compared to the thickness of gold oxide formed via oxygen plasma on planar surfaces. 34 However, the extremely sharp geometry of the gold tip would allow oxide formation on both the tip and the sides of the sample, thus producing a much larger apparent thickness than expected for a flat sample.…”

Section: Resultsmentioning

confidence: 99%

Three-Dimensional Atom Probe Tomography of Oxide, Anion, and Alkanethiolate Coatings on Gold

Zhang

Hillier

2010

Anal. Chem.

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We have used three-dimensional atom probe tomography to analyze several nanometer-thick and monomolecular films on gold surfaces. High-purity gold wire was etched by electropolishing to create a sharp tip suitable for field evaporation with a radius of curvature of <100 nm. The near-surface region of a freshly etched gold tip was examined with the atom probe at subnanometer spatial resolution and with atom-level composition accuracy. A thin contaminant layer, primarily consisting of water and atmospheric gases, was observed on a fresh tip. This sample exhibited crystalline lattice spacings consistent with the interlayer spacing of {200} lattice planes of bulk gold. A thin oxide layer was created on the gold surface via plasma oxidation, and the thickness and composition of this layer was measured. Clear evidence of a nanometer-thick oxide layer was seen coating the gold tip, and the atomic composition of the oxide layer was consistent with the expected stoichiometry for gold oxide. Monomolecular anions layers of Br− and I− were created via adsorption from aqueous solutions onto the gold. Atom probe data verified the presence of the monomolecular anion layers on the gold surface, with ion density values consistent with literature values. A hexanethiolate monolayer was coated onto the gold tip, and atom probe analysis revealed a thin film whose ion fragments were consistent with the molecular composition of the monolayer and a surface coverage similar to that expected from literature. Details of the various coating compositions and structures are presented, along with discussion of the reconstruction issues associated with properly analyzing these thin-film systems.

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“…The results seem to suggest that the gold surface is unchanged upon dip coating, without detectable traces of oxidization. However, previous studies have demonstrated that the Au surface can be oxidized by oxygen plasma treatments [31], therefore we can not exclude that, at least a small portion of the methoxysilane on the polymer might condensate with oxidized gold atoms strengthening the binding between the polymer and the surface which primarily is due to non covalent interactions such as van der Waals or hydrophobic forces.…”

Section: Polymeric Coating Characterizationmentioning

confidence: 90%

Functionalization of gold surfaces with copoly(DMA-NAS-MAPS) by dip coating: Surface characterization and hybridization tests

Petti

Torti

Damin

et al. 2014

Sensors and Actuators B: Chemical

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a b s t r a c tIn this work, a new method to functionalize a gold surface by dip coating with a functional copolymer is presented. The coating procedure is simple, robust and can be accomplished in less than one hour. Atomic force microscopy (AFM) scratch tests reveal the presence of a homogeneous polymer coating with a thickness of 2.5 nm. X-ray photoemission spectroscopy spectra from C1s, N1s and O1s levels present the typical fingerprints of the polymeric overlayer, i.e. the characteristic peaks from CNC O and NC O groups.Surface plasmon resonance (SPR) binding assays were used to check the coating functional properties. Immobilization of heparin to SPR gold surfaces functionalized with copoly(DMA-NAS-MAPS)-followed by binding analysis with the well known heparin binding protein fibroblast growth factor 2 yield binding kinetic parameters comparable to those obtained with commercially available carboxymethyl dextranfunctionalized sensorchips, thus confirming the great potential of the proposed technique.

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Alkanethiol Monolayers on Preoxidized Gold. Encapsulation of Gold Oxide under an Organic Monolayer

Cited by 176 publications

References 4 publications

Quantifying thiol–gold interactions towards the efficient strength control

Quantifying thiol–gold interactions towards the efficient strength control

Three-Dimensional Atom Probe Tomography of Oxide, Anion, and Alkanethiolate Coatings on Gold

Functionalization of gold surfaces with copoly(DMA-NAS-MAPS) by dip coating: Surface characterization and hybridization tests

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