Preparation and Characterization of Mesoporous Silica Thin Films with Vertically Aligned Channels on Substrates

Mesoporous organic/inorganic hybrid films with vertically aligned channels were in high interest but scientifically challenging, since there was no clear guidance to attain the surface-mediated vertical alignment. Here we developed a facile route to prepare meosporous silica thin films with a ternary surfactant system- C16TAB, SDS and P123, the structure directing agent, via sol-gel process. The thin films were then spin coated on silicon wafers and glass slides, and/or dipped in the coating solution for potential applications, such as catalyst support films, separation technology, optoelectronics, and high-density memory storage.
In the first part of this thesis, we used triblock copolymer P123 (EO20PO70EO20) as template, through sol-gel method, the mesoporous silica SBA-15 platelet (⊥) could be synthesized. From TEM and microtome TEM, we confirmed that the plate possessed well-ordered hexagonal structure and perpendicular channels. By changing the synthesis condition, for example, pH value and aging time, we looked forward to discovering better mesoporous silica SBA-15 platelet (⊥) synthesis condition. In the second part of this thesis, we modified the surface properties of silicon wafers and glass slides with some functional groups to help induce the vertical orientation of mesoporous organic/inorganic hybrid film channels on substrates. By sol-gel process and spin coating technique, the vertically aligned channel with hexagonally arranged and large pore size mesoporous organic/inorganic hybrid films could be formed uniformly in large scale. The structural characterization of the thin films was evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, grazing incidence small angle X-ray scattering (GISAXS) was used to investigate the structure and morphology of thin films.