Types of Sol-Gels

Silanes used for ormosil manufacture are a family of organo-silicon monomers with the general formula R-Si(OR )j, 

Precursors, which generally are di- and trifunctional silanes, span a wide range of sizes, chemical reactivities and functionalities. The use of precursors containing non-hydrolyzable SiC bonds, such as bifunctional or/and trifunctional alkoxysilanes (R Si(OR), n = 1 to 3, R = alkyl, R = organic group), allows introduction of organic groups directly bonded to the polymerlike silica network. Trifunctional alkoxysilanes 

The adsorption of organic compounds on metal substrates is generally achieved by two ways. Organic compounds are either adsorbed from the electrolyte similar to other conventional inhibitors, or adsorbed onto the metal surface by 

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Figure 6. Tip of the 20-pm tip of a fiber optic oxygen microsensor. The tip is coated with a ormosil-type of sol-gel doped with a ruthenium indicator for oxygen that display red luminescence. The sensor measures its decay time as a function of oxygen partial pressure.

In this pjqjer we report construction of redox electrolytes based on a new type of sol-gel... 

The chemical composition of sol-gels is typically a basic inorganic oxide. A common example of a sol-gel is silica gel, which has particular utility as stationary phase supports in chromatographic columns. The sol-gel materials used for electrode modification are typically created from two different classes of material inert and redox active. Many different types of sol-gels are derived from these classes, as outlined in Table 8.7 (113). 

Introduction of guest species into class one and two sol-gels can be accomplished through a variety of techniques (113), including chemical reactions and impregnation schemes. These procedures yield many different types of sol-gels that can be classified... 

Figure 26-4. Schematic outline for processing of two different types of sol/gel coatings (a) aminosilane coated SiOz soVgels (b) amino-functionalized hybrid sol/gels.

Alkoxides are mainly used as reagents in the sol-gel method, but inorganic or organic salts are also used. In this way, two types of sol-gel processes are developed in an alcoholic (organic) or an aqueous medium. 

The possibilities offered by the sol-gel method for obtaining nanosized powders were reviewed. The influence of nanosized oxide powders obtained by different types of sol-gel methods on their sintering behavior was evaluated. 

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