Novel Silica Hybrid Xerogels Prepared by Co-Condensation of TEOS and ClPhTEOS: A Chemical and Morphological Study

Abstract

The search for new materials with improved properties for advanced applications is, nowadays, one of the most relevant and booming fields for scientists due to the environmental and technological needs of our society. Within this demand, hybrid siliceous materials, made out of organic and inorganic species (ORMOSILs), have emerged as an alternative with endless chemical and textural possibilities by incorporating in their structure the properties of inorganic compounds (i.e., mechanical, thermal, and structural stability) in synergy with those of organic compounds (functionality and flexibility), and thus, bestowing the material with unique properties, which allow access to multiple applications. In this work, synthesis using the sol-gel method of a series of new hybrid materials prepared by the co-condensation of tetraethoxysilane (TEOS) and 4-chlorophenyltriethoxysilane (ClPhTEOS) in different molar ratios is described. The aim of the study is not only the preparation of new materials but also their characterization by means of different techniques (FT-IR, 29Si NMR, X-ray Diffraction, and N2/CO2 adsorption, among others) to obtain information on their chemical behavior and porous structure. Understanding how the chemical and textural properties of these materials are modulated with respect to the molar percentage of organic precursor will help to envisage their possible applications: From the most conventional such as catalysis, adsorption, or separation, to the most advanced in nanotechnology such as microelectronics, photoluminescence, non-linear optics, or sensorics.

Site-specific molecular design of low-dielectric benzocyclobutene (BCB)-sub-nanometer inorganic nanocomposites

“…Table S2 summarized the vibrations and structures of Si-O-Si. Si-O-Si stretching vibrations (~ 1020 cm − 1 ) corresponded to the lineal siloxane and cyclic trimers 43,44 , while asymmetric Si-O-Si stretching vibration at ~ 1050 cm − 1 (Peak 2) indicated ladder structures 44,45,46 . The characteristic peak at ~ 1080 cm − 1 (Peak 3) was attributed to ladder/cage-like or network structures.…”

Tunability of Hybrid Silica Xerogels: Surface Chemistry and Porous Texture Based on the Aromatic Precursor

“…Among the T species, the semi-condensed ones, T 2 , are the most abundant for all the materials, denoting that the complete condensation of the organic precursors is not favoured during the sol-gel process. Additionally, in the spectra of the Ph(TEOS) 2 series, a new signal emerges at −61 ppm as the content of the precursor increases, which corresponds to the least condensed silicon species (T 1 ) and has not been detected in previously studied hybrid materials [43,44]. In both series, the Q 3 /Q ratio decreases with the molar percentage of precursor, while the T 3 /T ratio increases, reaching the T 2 /T ratio at the highest molar percentages of precursor.…”

Hydrolysis and condensation behavior of tetraethoxysilane, hexaethoxydisiloxane, and octaethoxytrisiloxane

“…Progression of trimethylsilylation was con rmed by FTIR (Figure S2), by the appearance of the adsorption bands corresponding to δSi-Me (approximately 1250 cm − 1 ) and ρSi-Me (approximately 840 cm − 1 ), and the no appearance of the band corresponding to υSi-OH (approximately 950 cm − 1 ) [34,40,41]. No υSi-O-Si adsorption band was observed at 1200-1100 or 1040-1000 cm − 1 ; hence, the main structures of ethoxysilane-TMSs could be attributed to their linear, branched, and cyclic forms [34,42].…”