Preparation and Characterization of Hydrophobic Mesoporous SiO2 Aerogel

Abstract

Hydrophobic mesoporous silica aerogels were synthesized using cheap industrial grade tetraethyl orthosilicate (TEOS) as precursor by ambient pressure drying.The silica alcogels were prepared by acid-base sol-gel polymerization of the TEOS, the surfaces of silica alcogels were modified using trimethylchlorosilane/ hexamethyldisiloxane via simultaneous solvent exchange and surface modification. The attachment of trymethylsilyl (-Si(CH3)3) groups to the silica surface was confirmed by the presence of Si-CH3 peaks at 2963, 1256 and 845 cm−1 in the IR spectra. Properties of the aerogels were examined by SEM, TEM, XRD, BET and DTA-TG analyses. The results indicate that the aerogels in a typical amorphous state have a highly porous network with an average pore diameter in the range of 5–10 nm, have high specific surface area (931 m2/g) and are thermally stable up to 322 °C.