Characteristics, Chemical Modification Processes as well as the Application of Silica and its Modified Forms

Abstract

The variety of chemical modifications of the surface of silica and its modified forms cause these materials to find a consistently wider scope of application. In the publication, the characteristics of silica, silica gel, aerogel and xerogel are presented. The obtainment, application and properties of these materials are discussed. Methods of chemical modifications of surface structures with the use of different chemical compounds are presented. Special attention is turned to the behavior of silica and its modified form during the adsorption process. The main applications of silica and its different forms in analytical chemistry are also discussed.

Modification of the glass surface with hydrophobic silica thin layers using tetraethylorthosilicate (TEOS) and trimethylchlorosilane (TMCS) precursors

“…At this stage, further shrinkage also occurs; hence, the silica polymer structure becomes denser. This result is in line with the research of Rao et al, 44 which explained that xerogel TMCS and silane precursors with the trimethyl group could withstand up to temperatures of 300 C, which was characterized by a drastic decrease at temperatures of 300 C. 44,45 These TGA results are matched with contact angle data, which show that the TMCS-TEOS silica thin layers calcined at high temperatures (more than 300 C) have lower hydrophobicity and even tend to be hydrophilic as the hydrophobic group had decomposed.…”

First examples of organosilica-based ionogels: synthesis and electrochemical behavior

“…In general, silica materials made from acetone have larger surface areas than the materials made from methanol. The surface areas are remarkably high for monolithic silica materials dried under ambient conditions (xerogels) [ 49 – 50 ]. Moreover, many mesoporous systems collapse because of the strong forces applied to the pore walls by the evaporating solvent [ 49 ]; this is, however, not the case here.…”

Immobilized ruthenium complexes and aspects of their reactivity

“…This is well illustrated by the extensive number of proposed reactions for chemically functionalized silica gel, which encompasses both inorganic and organic reactions [30]. For example, the reaction of an appropriate organosilicon compound, via the stable Si-O-Si-C moiety or metal alkoxide reaction with the silica surface [69], can form a layer of desirable specific functional groups that will promote interaction with the complex of interest.…”