Formation of lamellar silica from lyotropic liquid crystals of dodecyl benzene sulfonic acid

The formation of lamellar mesostructured silica by a neutral route in dodecylbenzene sulfonic acid (DBSA)/aminoalkoxysflane/water systems was investigated by phase study and Small Angle X-ray Scattering (SAXS). Initially, two lamellar lyotropic phases are found, one corresponding to the DBSA and other corresponding to the DBSA-aminoalkoxysilane salt. With the hydrolysis and condensation of siloxane groups, the DBSA-aminoalkoxysilane Iyotropic phase disappears and lamellar silica is formed. The lyotropic phase does not act as a true template but as a source of amphiphilic molecules, hence synthesis takes place via a phase separation mechanism. This synthesis route provides an easy way to prepare amino functionalized. lamellar silica.