Silanization is the covering of a surface through self-assembly

Self-assembly

Self-assembly is a term used to describe processes in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction...

 with organofunctional alkoxysilane molecules. Mineral components like Mica

Mica

The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...

, glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

 and metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 oxide

Oxide

An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....

 surfaces can all be silanized, because they contain hydroxyl

Hydroxyl

A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 groups which attack and displace the alkoxy groups on the silane thus forming a covalent -Si-O-Si- bond. The goal of silanization is to form bonds across the interface between mineral components and organic components present in paints, adhesives...

Properties

Organofunctional alkoxysilane molecules have both organic and inorganic properties.

Organofunctional alkoxysilanes

The alkoxy groups usually used are the methoxy

Methoxy

In chemistry , methoxy refers to the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula O–CH3.The word is used in organic nomenclature usually to describe an ether...

 (-OCH₃) and the ethoxy (-OCH₂CH₃) groups. The organofunctional alkoxysilanes are classified according to their organic functions:

Aminosilanes

The organic function is a primary or secondary amine

Amine

Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...

:

• APTES (3-aminopropyl)-triethoxysilane CAS# 919-30-2
• APDEMS (3-aminopropyl)-diethoxy-methylsilane
• APMES (3-aminopropyl)-dimethyl-ethoxysilane
• APTMS (3-aminopropyl)-trimethoxysilane CAS# 13822-56-5

Glycidoxysilanes

The organic function is an epoxide

Epoxide

An epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...

:

• GPMES (3-glycidoxypropyl)-dimethyl-ethoxysilane

Mercaptosilanes

The organic function is a thiol

Thiol

In organic chemistry, a thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl group...

:

• MPTS (3-mercaptopropyl)-trimethoxysilane
• MPDMS (3-mercaptopropyl)-methyl-dimethoxysilane