NMR and IR spectroscopy of silica aerogels with different hydrophobic characteristics

H. El Rassy , A.C. Pierre (1)

1 IRC - Institut de recherches sur la catalyse

Silica aerogels, prepd. by the sol-gel method and dried by the CO2 supercrit. method, were produced from tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS) in different proportions, to change the proportions of hydrophilic and hydrophobic surface groups. The aerogel hydrophobic or hydrophilic properties were related to their surface structural characteristics. The relative proportion of Si-OH, Si-OCH3 or Si-CH3 groups present on the aerogel pore surface and its silica network structure were detd. by 1H, 29Si and 13C NMR. The results obtained were correlated with the IR transmission spectra. From these data, a possible description of the mixed hydrophilic-hydrophobic nature of the surface of these materials is proposed.

Domaines: Catalyse

H. El Rassy, A.C. Pierre. NMR and IR spectroscopy of silica aerogels with different hydrophobic characteristics. Journal of Non-Crystalline Solids, 2005, 351 (19-20), pp.1603-1610. ⟨hal-00012513⟩