关键词: 气凝胶;疏水性;改性

Abstract: Nano-porous hydrophobic SiO2aerogels were prepared via ambient pressure drying method with tetraethoxysilane(TEOS)as precursor and ammonium fluoride(NH4F)as catalyst.TMCS was used as hydrophobic modifiers,so as to reduce shrinkage and collapsing of the sample during of the application. The results show that the bulk density,thermal conductivity and specific surface area of TMCS modified SiO2aerogels are 0.191 g/cm3, 0.031 W/(m· K)and 667 m2/g, respectively.The experimental results of SEM and TEM show that SiO2aerogels have amorphous nano-mesoporous structure.The results of contact angle test prove that the contact angle of TMCS modified SiO2aerogels could reach 147°,so it shows good hydrophobicity.After heat treatment at 400℃,the aerogel becomes hydrophilic because it is lost most of its hydrophobic groups(-CH3).

Key words: aerogel;hydrophobicity;modification