Gold surface

Gold coating of glass surfaces is carried out by modem vacuum deposition (PVD, physical vapor deposition) and also with an old method, painting with a gold pigmented lacquer, followed by burning. 

For assaying, the cupellation test is used. The method is described by Agricola and is 

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As a somewhat anecdotal aside, there has been an interesting question as to whether gold is or is not wet by water, with many publications on either side. This history has been reviewed by Smith [119]. The present consensus seems to be that absolutely pure gold is water-wet and that the reports of non wetting are a documentation of the ease with which gold surface becomes contaminated (see Ref. 120, but also 121). The detection and control of surface contaminants has been discussed by White [121] see also Gaines [122]. 

A detailed study by Grieser and co-workers [169] of the forces between a gold-coated colloidal silica sphere and a gold surface reveals the preferential adsorption of citrate ions over chloride to alter the electrostatic interaction. 

Akiyama T, Imahori H, Ajawakom A and Sakata Y 1996 Synthesis and self assembly of porphyrin-linked fullerene on gold surface using S-Au linkage Chem. Lett. 907-8... 

In contrast to the gold surface, on silver the chains adopt a lower tilt angle of 12° from the surface nonnal [160,... 

Covalent immobilization of proteins on nricrostmctured gold surfaces was studied in [226]. On Arese substrates, which were prepared by pCP aird etching. Are immobilization sites of proteins could be spatially controlled using air amino-reactive SAM. The whole process, i.e. production of Are micropattemed substrate including SAM exchairge aird protein immobilization, took a reasonably small amount of time ( 24 h), providing some flexibility in the experimental work. 

Stouffer J M and McCarthy T J 1988 Polymer monolayers prepared by the spontaneous adsorption of sulphur-functionalized polystyrene on gold surfaces Macromolecules 2 1204-8... 

Figure 8.18 shows an X-ray photoelectron spectrum of gold foil with mercury absorbed onto the surface. Both the gold and mercury doublets result from the removal of a 4/ electron leaving /2 and /2 core states for which L = 3, S = and J = or Less than 0.1 per cent of a monolayer of mercury on a gold surface can be detected in this way. 

Chemisorption of alkanethiols as well as of di- -alkyl disulfides on clean gold gives indistinguishable monolayers (251) probably forming the Au(l) thiolate species. A simple oxidative addition of the S—S bond to the gold surface is possibly the mechanism in the formation of SAMs from disulfides ... 

In the alkanethiol case, the reaction may be considered formally as an oxidative addition of the S—H bond to the gold surface, followed by a reductive elimination of the hydrogen. When a clean gold surface is used, the proton probably ends as a molecule. Monolayers can be formed from the gas phase (241,255,256), in the complete absence of oxygen ... 

The relative intensities of the bands in the transmission and RAIR spectra were used to determine the orientation of the long axis of the 4-MPP molecules with respect to the normal to the gold surface. It was found that this tilt angle was about 21°, a value that was similar to that obtained from molecular dynamics simulations [11]. 

When the gold surface is completely covered with HI molecules, increasing the concentration of HI(g) has no effect on reaction rate. 

More recently, self-assembling 3//-azepine monolayers on a gold surface have been obtained by the photodecomposition of bis ll-[(4-azidobenzoyl)oxy]undec-l-yl disulfide.284 Other than some alkyl and aryl 177-azepine-l-carboxylates, which possess fungicidal activity, particularly against Sclerotium rolfsii,104 the unsaturated azepine systems surveyed in this section do not have any notable biological activity. 

The value of Emin in the pseudo-stable state has been found to increase in the sequence (111) (100)single-crystal faces in aqueous solutions. It has been concluded that the Au-DMSO interactions vary much more with the atomic structure of the gold surface than the Au-H20 interactions and that the Au-DMSO interactions are stronger than forH20.477 Following Trasatti s relation,7 the values of A(<5 m - have been obtained for different planes of Au. It has been found that the difference (<5/M - S/s) for Au( 110) and Au( 111) planes is greater than 0.5 V.477 It should be noted that the same order of Au( 111) and Au(210) has been found in a 2.5 x 10-3 M KPF6 + AN solution.63,392,477... 

The temperature behavior of low446,491,503 558 as well as high Miller index crystal faces of Au447,448 has been examined in 0.01 M perchloric acid solutions. For all gold surfaces studied, C, was found to decrease and Ea=Q moved to less negative values with increasing t 446-448 491503-558... 

Flade potential, 247 Flame-annealed gold surfaces and the work of Kolb, 81 Flat band potential, 483 Fluctuations asymmetrical and unstable systems, 255 controlling progress in pitting, 299 in pitting dissolution, 251 and corrosion processes, 217 during dissolution, 252 at electrodes, theory, 281 during film breakdown, 233 and mathematical expressions thereof, 276... 

The experimental results in Fig. 26 have a further implication that the nominal value of surface energy does not associate directly with the friction level. The FFM measurements of friction force between gold surfaces and Si tips... 

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