A theoretical and experimental study of the possible phenytriethoxysilane species found on treated silica

A modified extended Huckel molecular orbital (EHMO) method, which includes core-core repulsion terms, was used to study the silane adsorption on SiO2 surfaces. The SiO2 treated at 300 degrees C was chemically modified with an alcoxysilane, phenyltriethoxysilane (PTES). Therefore, we study the possib le adsorption of PTES on two planes (with isolated and geminal silanols) an d the possible species formed once the reaction with a SiO2 surface is fini shed. Starting from this analysis, it is possible to evaluate the PTES sele ctivity to the different anchoring points on the SiO2 surface. (C) 2000 Els evier Science B.V. All rights reserved.