Preparation and characterization of surface-functionalized polysilsesquioxane hard spheres in aqueous medium

Nanosized silica and functionalized silica spherical particles have typically been made by complex methods, which were then used as template materials to fabricate nanostructured materials. However, in a simple one-step hydrolytic co-condensation process, we synthesized various sizes of nano/micro hard spheres of functionalized network polysilsesquioxanes, similar to functionalized silica, of narrow size distribution from heterogeneous mixtures of organomethoxysilanes, surfactants, water, and ammonium hydroxide solution. The size of the spherical polysilsesquioxanes particles could be controlled from nanometer to micrometer by adjusting and changing the organomethoxysilane composition, the molar ratio, and the catalyst concentration. The resulting monodisperse particles possessed surface organic functional groups having similar properties and applications as found in functionalized silica spherical particles. The functional polysilsesquioxane spherical particles were characterized by scanning electron microscopy and dynamic light scattering to elucidate the particles' morphologies. The compositions of the polysilsesquioxanes were confirmed by FT-IR spectroscopy, solid-state NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and elemental analysis.