synthesis and characterization of hydrophobic silica aerogel by two step(acid-base) sol-gel process

the silica aerogel was prepared by the acid–base sol–gel polymerization of tetraethylorthosilicate precursor followed by ambient pressure drying. the prepared silica aerogels were characterized by fourier transform infrared )ft-ir(, thermo-gravimetric and differential thermal analysis )tg/dta(, x-ray diffractometer )xrd(, energy dispersive x-ray microanalysis )edx(, brunauer–emmitt–teller (bet)  and scanning electron microscopy (sem). the result silica aerogel is a light and crack-free solid with very low bulk density 0.027 g /cm3, high specific surface area 655.58 m2/ g and large pore volume 0.4831 cm3/ g. the average size of particles was calculated using a microstructure measurement program and minitab statistical software.