Synthesis of hydrophobic silica aerogel by the sol-gel polymerization method with precursor tetraethoxysilane

Hydrophobic silica aerogels were synthesizad by two step acid-base catalyzed sol-gel polymerization of precursor tetraethoxysilane (TEOS), followed by supercritical drying of alcogels with carbon dioxide (CO2). in the synthesis, HCL and NH4OH are the hydrolysis and condensation catalysts respectively. To make the gels hydrophobic, the gels were washed with a mixture containing trimethylchlorosilane (TMCS) and n-hexane for silylation. The hydrophobicity of the aerogels was tested by measuring the contact angle (Ө) and Fourier transform infrared spectroscopy (FTIR) indicates the chemical bonding state of aerogels

Keywords:

Hydrophobic silica aerogel , sol-gel polymerization , Tetraethoxysilane (TEOS) , Supercritical drying , trimethylchlorosilane (TMCS)