Silanization

Silanization is called a chemical attachment of a silane compound to a surface. The connection is made by condensation reactions between the hydrolyzable groups of the silanes used and the chemical groups on the surface.

Mechanism

The silanes used for the silanization have the general form RmSiXn, where R is organically functionalized radicals and X of hydrolyzable groups (usually alkoxy groups, more rarely -Cl) are, ie, they can by hydrolysis with water silanols form RMSI (OH ) n form. Similarly, they may (or the silanols formed by them ) with OH or COOH groups react at surfaces and form a composite, as shown in the figure.

Objectives of silanization

The properties of the coated surface will depend on the silane used. The main applications concern the adhesion of subsequently applied coatings and the realization of non-stick coatings. The silanes can either be applied directly to the surfaces ( eg in biochemistry often 1,7- dichloro -1 - ,1,3,3,5,5,7,7 octamethyltetrasiloxane than 5 % solution in heptane directly on coated glass in order to produce on a temporary non-stick coating ) or it may first be produced, a primer, for example, by flame coating or physical vapor deposition, to which the silanes can then be firmly anchored.

An important example of the silanization the two -stage process is the application in the dental art to combine different materials together, or to coat the metal surfaces with ceramic components. Since mechanical connections under oral conditions would resolve after a certain time, a primer is first generated by " silicatization " and it anchored by " silanization ", the adhesion promoter, which connects the two dental materials firmly together. The resultant bond strength is superior by " direct" silanization, ie without generating a substrate, it is achievable far.