Silicate glass surfaces

Myhra, S., Smart, R. St. C. Turner, P. S. 1988fc. The surfaces of titanate minerals, ceramics and silicate glasses surface analytical and electron microscope studies. Scanning Microscopy, 2, 715-734. 

Webb EB, Garofalini SH (1994) Effect of adsorption of EAM metal atoms on the structure of a sodium alumino-silicate glass surface a molecular dynamics simulation. Surf Sci 319 381-393... 

Mekki, A., Holland D. McConville, C. F. (1997). X-ray photoelectron spectroscopy study of copper sodium silicate glass surfaces. Journal of Non-Crystalline Solids, 215(2-3), 271-82. 

Table 8. Effect of Ar ion bombardment on the atomic structure of the lead-silicate glasses surface layers...

Enzyme adsorption by cellulose films was observed by several methods, including XPS, and was followed by enzymic degradation of the films. Silicate glass surfaces were found to be depleted in Fe and Al as a result of exposure to Bacillus sp. XPS revealed that reduced sulfur forms in aqueous solutions of coal-derived products were not oxidized by dibenzothiophene-degrading bacteria, supporting the indication that extensive degradation of the carbon structure was concurrent with the loss of sulfur. In the context of the extraction of iron from a hornblende by Arthrobacter sp., the formation of siderophore-Fe surface complexes was examined by an XPS study of Fe with and without the siderophore on gold surfaces, and of the siderophore on hornblende crystal surfaces. ... 

The polymer (CTA, A/= 3.3x 10, acetate number 62.5), prepared as a cotton-wool by reprecipitation, was thoroughly purifies from aromatic additives by extraction by methanol. Analytically pure naphthalene was additionally sublimated. Films 6 - 20 pm thick were prepared from polymer and naphthalene solution in methylene chloride. The solution was distributed by the silicate glass surface and the solvent evaporated. After solvent removal, the films were stratified by water and dried in vacuum during 24 hours. 

The measured potential is thus a linear function of pH an extremely wide (10-14 decades) linear range is obtained, with calibration plots yielding a slope of 59 mV per pH unit. The overall mechanism of the response is complex. The selective response is attributed to the ion-exchange properties of the glass surface, and in particular the replacement of sodium ions associated with the silicate groups in the glass by protons ... 

Sodium-silicate glass, 151 Sol-gel films, 120, 173 Solid electrodes, 110 Solid state devices, 160 Solvents, 102 Speciation, 84 Spectroelectrochenristry, 40 Spherical electrode, 6, 8, 9, 61 Square-wave voltammetry, 72, 92 Staircase voltammetry, 74 Standard potential, 3 Standard rate constant, 12, 18 Stripping analysis, 75, 79, 110 Supporting electrolyte, 102 Surface-active agents, 79... 

Some of the compounds described in this chapter were studied for specific physical properties. Surface tension measurements with solutions of 9-16 in 0.01 M hydrochloric acid demonstrated that these zwitterionic X5Si-silicates are highly efficient surfactants.21 These compounds contain a polar (zwitterionic) hydrophilic moiety and a long lipophilic z-alkyl group. Increase of the n-alkyl chain length (9-15) was found to result in an increase of surface activity. The equilibrium surface tension vs concentration isotherms for 9 and 16 were analyzed quantitatively and the surface thermodynamics of these surfactants interpreted on the molecular level. Furthermore, preliminary studies demonstrated that aqueous solutions of 9-16 lead to a hydrophobizing of glass surfaces.21... 

Figure 15. Amplitude -time plots obtained from AFM measurements for the decay of sinusoidal 1-D gratings with the periods indieated on the surface of a silicate glass(Corning 1737) annealed in air at827C.[42], The exponential decay constant scales approximately as q as expected for a viscous flow controlled process[l].

Vitreous silica is susceptible to attack by alkaline solutions, especially at higher concentrations and temperatures. For 5% NaOH at 95°C, although crazing may be evident, surface corrosion is only 10 Jim after 24 h (87). For 45 wt % NaOH at 200°C, dissolution proceeds at 0.54 mm/h (88). The corrosion rates in other alkaline solutions are Us ted in Table 3. Alkaline-earth ions inhibit alkaline solution attack on vitreous silica. Their presence leads to the formation of hydrated metal silicate films which protect the glass surface (90). 

The surface conductivity of vitreous silica is also low compared to other silicate glasses. Because vitreous silica is not hydroscopic, water Alms containing exuded alkalies do not readily form on its surfaces. The surface conductivity, however, can increase signiAcantly with increasing relative humidity. A change in the relative humidity from 20 to 80% produces a millionfold increase in the surface conductivity (174). 

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