Glass surface resistance

Transparent ionomer coatings are appHed to glass surfaces to improve safety characteristics (39). Special types of ionomers are used as interlayers between glass sheets for appHcations requiring penetration resistance (40). 

Other Applications. The refractive index of siUcate or borosiUcate glass can be modified by the addition of cesium oxide, introduced as cesium nitrate or carbonate. Glass surfaces can be made resistant to corrosion or breakage by surface ion exchange with cesium compound melts or solutions. This process can also be used for the production of optical wave guides (61). 

A window consisting of a single piece of clear glass can also he treated with R-value analysis. As with the wall, there is convective and radiative heat transfer at the two surfaces and conductive heat transfer through the glass. The resistance of the window is due to the two surface resistances and to the conductive resistance of the glass, For typical window glass, R = 0.003 (W/ni -°C)" (0.02 (Btu/h-ft -°F) ) so the total resistance of the window is = (0.12 + 0.003 + 0.04) (W/m -- C) ... 

The data indicate that the properties of the lower glass transition temperature metal ion modified polyimides are altered more than the properties of the higher glass transition temperature metal ion modified polyimides. Extraction removes both cobalt and chlorine from the films and slightly increases bulk thermal stability and both surface resistivity and bulk electrical resistivity. Details pertaining to the structure, analysis and properties of these novel gradient composites are discussed. 

By using a pattern of two different types of biomolecules on the surface, it is possible to tailor the surface regions that are cell adhesive and cell resistant. Feng et al. showed that by covalent p,CP of chitosan onto an aldehyde-enriched glass surface followed by incubation in BSA solution, the surface will have properties for cell localization and cell growth guidance.110... 

Whenever there is a chemical erosion of glass, water or its dissociation products, H+ or OH ions will be involved. Because of this, a distinction is made between the resistance of glass to water (its hydrolytic resistance) and to alkali or acid. Under attack from water or acids, small numbers of cations, particularly monovalent and divalent, are released. On resistant types of glass, a very thin layer of silica gel forms in this way on the glass surface and usually inhibits further erosion. In contrast, hydrofluoric acid, alkaline solutions and, under certain circumstances, phosphoric acid will slowly remove the inhibitor layer and thus the entire surface. Nonaqueous solutions (organic solutions), however, are practically nonreactive with glass. 

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