Organosilane molecule

This section will cover aspects of monohydride terminal surface reactions that were carried out under free-radical conditions. The description will be circumscribed to the reactions with molecular oxygen and monounsaturated compounds. Mechanistic information for these reactions is scarce mainly due to the complexity of the system, and mechanistic schemes are often proposed in analogy with radical chemistry of organosilane molecules. H—Si(lll) has a band gap of about 1.1 eV while the HOMO LUMO gap in (Me3Si)3SiH is within 8-11 eV and, therefore, has very important consequences for the reactions with nucleophilic and electrophilic species where frontier orbital inter-... 

Fig. 4. Four types of organosilane molecules used and their molecular structure.

Fig. 10. Molecular chain lengths of four types of organosilane molecules calculated by using ab initio molecular orbital theory. The -Si(OCH3)3 was converted to the -SiH3 for the model molecules used in the calculation using GAUSSIAN 98.

Recently, ultrathin organic thin films attract attention as new film lubricant [51]. Organosilane monolayer, which is one of the ultrathin films, has been identified as promising boundary lubricants. This is because organosilane molecules interact strongly with substrates and they are robust against solvent and temperature increase. Friction and wear tests of monolayers were carried out with a conventional ball-on-disk type friction tester (SHINTO Scientific Co. Ltd.) in air and tetradecane at 298 K. A 5.0 mm radius ball made of stainless steel was slid on a disk. The friction coefficient was determined by the distortion of a... 

A similar strategy involving Laponite or MMT platelets grafted with polymerizable organotitanate and organosilane molecules was recently reported by Voorn et al. [285, 286]. Here, starved-feed soap-free emulsion polymerization of MMA conducted in the presence of the organoclay led to clay encapsulation. However the solid content was quite low (typically around 7%). 

Mekhalif and coworkers [165] adopted the other approach, that is, assembly of organosilane molecules on oxide-covered stainless steel. The substrate was bulk stainless steel, polished, cleaned, and sonicated. Two organosilanes of similar chain length, a trichlorosilane, and a triethoxysi-lane, both terminated with hydrophobic... 

The economical losses due to the corrosion of infrastructure and equipment worldwide are immense. It is therefore relevant that coatings be applied to metal substrates — organosilane molecules have the unique capability to form strong covalent bonding with the metal substrate [17]. 

Among the organosilane molecules that can be used as pre-treatments for corrosion protection of metallic substrates, bis-functional silanes have attracted special attention. Example of these silanes are the bis-[triethoxysilylpropyl] tetrasulphide (BTESPT) and bis-1,2-[triethoxysilyl] ethane (BTSE). Electrochemical measurements and accelerated corrosion tests, such as salt spray tests, show that these silanes provide enhanced corrosion protection of different metallic substrates [38 6]. This... 

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