Periodic Mesoporous Organosilica Materials Incorporating Various Organic Functional Groups: Synthesis, Structural Characterization, and Morphology

Abstract

We describe the syntheses and characterization of a series of periodic mesoporous organosilica (PMO) materials containing various organic functional groups prepared using the direct synthesis method under basic conditions. This synthetic method allows the production of mesoporous organosilicas that have large surface areas and contain several different functional groups, such as a bridged amino, vinyl, ethyl, glycidoxypropyl, and cyanopropyl units. Moreover, the type of organosilane used as a co-precursor has a great influence on the final particle shape and modulates the overall properties of the resulting materials. By changing the precursor type, along with its concentration, the particles can adopt various morphologies, including rod-shaped and wormlike particles that have different degrees of bending. We propose a plausible mechanism to explain the formation of these shapes. We have used X-ray diffraction (XRD) patterns, nitrogen sorption properties, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and 13C and 29S magic angle spinning (MAS) NMR spectroscopy to characterize the structures and organic functionalities present in the resulting functionalized PMO materials.