ABSTRACT
The Concept of Amorphous Silica “Surface” . . . . . 332
Character of Surface Bonding . . . . . . . . . . . . . . . . . 332
Physical Parameters Describing
Surface State of Amorphous Silica . . . . . . . . . . . . 333
Minimal Temperature of Total Removing Physically
Adsorbed Water from Hydroxylated Surface . . 334
Concentration of Hydroxyl Groups on
Hydroxylated Silica Surface . . . . . . . . . . . . . . . 334
Dependence of Hydroxyl Group Concentration
on Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 335
Topography of Hydroxyl and
Hydrate Cover of Silica Surface . . . . . . . . . . . . . . 337
Electrostatic Aspects of Adsorption
on Silica Surface . . . . . . . . . . . . . . . . . . . . . . . . . . 342
Hydrophobic and Hydrophilic Properties of
Trimethylsilylated Silica Surface . . . . . . . . . . . . . 350
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
The structure has been examined and a description has been given of the active sites of silica surface as well
as of the principal macroscopic and microscopic parameters generally describing its structure. The influence
has been studied of the electric field of SiO2-surface layer on the properties of adsorption complexes and its
role has been investigated in the run of physico-chemical processes at the interface of solid-gas. The distri-
bution of near-surface electrostatic field has been shown to allow predicting the structure of primary adsorp-
tion complexes, to estimate the energetics of molecule transformation on solid surface, and to define the
properties of surface compounds formed. Within the frameworks of notions on distribution of molecular elec-
trostatic potential within the subsurface layer of modified silicas, their hydrophobic and hydrophilic proper-
ties have been studied. It has been discovered that there are small compact areas of negative potential value
within subsurface layer of even completely trimethylsilylated silica controlling its residual hydrophility.
