Functionalized mesoporous materials obtained via interfacial reactions in self-assembled silica-surfactant systems

A unique interfacial reactivity of self-assembled mesostructured silica-sur factant systems toward organosilanes was utilized to obtain ordered mesopor ous materials such as MCM-41 with different surface functionality. The idea of this process is based on a direct replacement of electrostatic interact ions between negatively charged silica species and surfactant cations by st rong siloxane bonds. The current study shows that any suitable organosilane , having at least one reactive group (Cl-Si=, EtO-Si=, MeO-Si=) in the stru cture, is able to displace template from self-assembled silica-surfactant m esostructures and form a covalent bonding with the silica surface. The afor ementioned displacement process allows for the synthesis of mesoporous mate rials with high degree of structural ordering, desired surface functionalit y and high coverage of bonded ligands. Also, a proper choice of silane and templating surfactant provides an opportunity to tune the pore size of the resulting materials. In addition, this process improves the stability of se lf-assembled mesoporous materials and preserves their structural ordering, which is not always achieved when the surfactant template is removed via ca lcination.