Hierarchical 3D-ordered macro-/mesoporous organosilicas with inverse opal morphology synthesized by a combination of nanocasting and pseudomorphic transformation
Here, we report the first synthesis of nanoporous organosilica hybrid materials with a hierarchical pore structure based on an inverse opal morphology. The synthetic route involves the acid-catalyzed exo-templating of a bis-silylated organosilica precursor followed by alkali-catalyzed pseudomorphic transformation endo-templating to generate materials with ordered arrangements on the macro-, meso- and molecular levels. The surface chemistry can be tuned using different precursors such as 1,4-bis(triethoxysilyl)benzene, 1,4-(E)-(bis(triethoxysilyl)vinyl)benzene and 2,5-(E)-(bis(triethoxysilyl)vinyl)aniline. It was shown by different analysis techniques that the presented synthetic route works well. The resulting benzene-bridged material combines an ordered macro- and mesoporous structure with a crystal-like orientation of the precursor molecules in the pore walls. The mesopores show a maximum diameter of 3.8 nm and a specific surface area of 948 m(2) g(-1). When the two divinyl precursor monomers are used, the resulting materials show a hierarchically porous organic-inorganic hybrid structure but no periodically ordered mesopores. This might be caused by the different chemical behaviors of the precursors. All the synthesised organosilica materials exhibit inverse opal structures and are potential candidates for application in release/storage, sensing, separation, adsorption, catalysis and others.