Naslov
The role and properties of the Si-O-Si and Si- N(H)-C bridges in silica network structure and polymer formation-a DFT study

Autori
Dananić, Vladimir ; Movre Šapić, Iva

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
17th European Symposium on Polymer Spectroscopy- Book of Abstracts / Wilhelm, P. - Graz : Austrian Centre for Electron Microscopy and Nanoanalysis, 2007, 43-43

Skup
17th European Symposium on Polymer Spectroscopy

Mjesto i datum
Leibnitz, Austrija, 09.09.2007. - 12.09.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
aminopropylsilanetriol ; DFT ; H-bonding

Sažetak
The polymerisation of various organosilicone compounds essentially depends on the formation of Si-O-Si bridge between monomers. Due to the inability of the oxygen atom to make more than two bonds, the angle of the Si-O-Si bridge is very flexible. This flexibility makes possible to form geometrically very different structures containing Si and O atoms. A few of these structures are studied theoretically by the DFT ab initio calculations. As a starting point to study the properties od the SiOSi bridge, we take the aminopropylsilanetriol (NH2(CH2)3Si(OH)3) compound and expose it to various polymerisation conditions. The appearence of the Si-O-Si bridge is detected, or undetected, by Raman spectroscopy. However, this compound has one more possibility to polimerise through Si-N-C bridge, with or without the H atom attached to the nitrogen atom. The necessity of the nitrogen to make three bonds makes this bridge stiffer than the Si-O-Si bridge, thus leading to a more rigid polymer than the polymer made by Si-O-Si bridge. The dimers made by the Si-O-Si or Si- NH-C bridges are isoelectronic, since in either case one water molecule is released in the formation of a dimer[1]. This fact enables us to compare calculated ground state energies of the two dimers directly, and see which one is more probable to occur in a water solution, according to Boltzmann distribution. Furthermore, the conditions of polymerisation seems to be essential for the occurrence of either bridge.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA