MOLECULAR SIMULATIONS OF THE POLYMERIZATION OF SILICIC-ACID MOLECULESAND NETWORK FORMATION

Citation
Sh. Garofalini et G. Martin, MOLECULAR SIMULATIONS OF THE POLYMERIZATION OF SILICIC-ACID MOLECULESAND NETWORK FORMATION, Journal of physical chemistry, 98(4), 1994, pp. 1311-1316
Citations number
37
Categorie Soggetti
Chemistry Physical
ISSN journal
00223654
Volume
98
Issue
4
Year of publication
1994
Pages
1311 - 1316
Database
ISI
SICI code
0022-3654(1994)98:4<1311:MSOTPO>2.0.ZU;2-C
Abstract
Polymerization of 216 silicic acid molecules, H4SiO4, has been studied using the molecular dynamics computer simulation technique. Multibody potentials which reproduce bulk and surface structures of silica and silicate glasses, as well as molecular configurations containing Si, O , and H ions, were used in the simulations. Results of the simulations are consistent with experimental data of sol-gel systems. Chains form at the early stages of polymerization, followed by ring formation, co nsistent with interpretations of NMR data and semiempirical molecular orbital quantum calculations. The activation energy for formation of b ranching Q(n) species is 12 kcal/mol, consistent with the experimental data of 12 kcal/mol for gelation. The relative time evolution of the various Q(n) species is consistent with experimental NMR data.