Spectral and structural investigation of silica aerogels properties synthesized through several techniques

Abstract

The paper presents fairly coverage for the made-up and characteristics of most different forms of aerogels progressed from the original systems of silica-based. The aerogels structural and spectral properties can be tailored through synthesizing techniques providing the requirements of the desired application. present a comparative investigation of the spectral and structural properties for silica aerogels derived from different preparation techniques. Seven samples synthesized through the sol-gel polymerization of tetraethylorthosilicate, tetramethylorthosilicate, and sodium silicate precursor, were tested. Some of these samples were hydrophobized using trimethylchlorosilane. The precursors were adopted independently in the preparation process. Supercritical carbon dioxide, ambient pressure, and freeze-drying techniques had been followed separately as drying techniques. The silica aerogels physical properties are examined through Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption-desorption, and scanning electron microscope (SEM) tests. Identically, surface-functionalized silica aerogels were acquired from a variety of aerogels, consequently, comparing their chemical structures. The recorded FTIR spectra pointed out chemically analogous existence of silica networks with some differences, commonly, due to the additive incorporated and the synthesizing techniques. The results show that; pore-size, morphology, and the hydrophobic tendency could be controlled through the selection of the starting precursor, drying technique, and starting pH.