SiO₂ aerogels prepared with ambient pressure drying and its properties

SiO₂ aerogels were produced from tetraethyl orthosilicate (TEOS) as silicon resources, ethanol as solvent and watery HCl or ammonia by sol-gel method and surface modification at ambient pressure. Scanning electronic microscopy, Fourier transform infrared spectrometer (FT-IR), pore size distribution measurement, packing density and some other experiment methods were used to characterize the morphology and pore structure and other properties of the silica aerogels. The results show that the silica aerogels have a typical nano-porous microstructure with hydrophobic property. It was discovered that SiO₂ aerogels have better properties when the preparation condition is as following: the watery HCl concentration is 1%, the aging reagent is CH₃CHOHC₄H₉, the aging time is 20d, the volume concentration of trimethylchlorosilane (TMCS) in hexane is 6% and the surface modification time is 24h.