Abstract Title
Synthesis of Ordered Mesoporous Silica
Additional Funding Sources
The project described was supported by a student grant from the UI Office of Undergraduate Research.
Abstract
Mesoporous silica nanochannels are an important material with uses in fields such as drug delivery, thermal energy storage, and filtration. The goal of this project was to gain a better understanding of the chemical relationships involved in the synthesis of mesoporous silica. Synthesis of mesoporous silica requires a surfactant template, a silica precursor, and a reaction catalyst. A technique was developed to ionically bind a nitrate catalyst to a cetrimonium bromide surfactant template. This cetrimonium nitrate surfactant was then used as a template. Several surfactant removal techniques were used to observe how structure was impacted during template removal. Electron microscopy confirmed the effective synthesis of ordered mesoporous silica particles. X-ray diffraction analysis showed that cetrimonium nitrate templates produced a structure nearly identical to cetrimonium bromide templated silica in a typical synthesis system. Cetrimonium nitrate was also used to template silica in a catalyst free system. X-ray diffraction of the catalyst free synthesis product showed the remnants of a structure that was likely destroyed during synthesis. X-ray data also indicated that calcination decreases d-spacing and causes peak broadening; while methanol-based removal at both room temperature and in a soxhlet extractor completely degrades the ordered structure. These results provide an understanding of how cetrimonium nitrate behaves as a template for mesoporous silica and how different surfactant removal techniques impact structure. Results also indicate that cetrimonium nitrate has the potential to be a self-catalyzing template which will be an interesting topic for future research.
Synthesis of Ordered Mesoporous Silica
Mesoporous silica nanochannels are an important material with uses in fields such as drug delivery, thermal energy storage, and filtration. The goal of this project was to gain a better understanding of the chemical relationships involved in the synthesis of mesoporous silica. Synthesis of mesoporous silica requires a surfactant template, a silica precursor, and a reaction catalyst. A technique was developed to ionically bind a nitrate catalyst to a cetrimonium bromide surfactant template. This cetrimonium nitrate surfactant was then used as a template. Several surfactant removal techniques were used to observe how structure was impacted during template removal. Electron microscopy confirmed the effective synthesis of ordered mesoporous silica particles. X-ray diffraction analysis showed that cetrimonium nitrate templates produced a structure nearly identical to cetrimonium bromide templated silica in a typical synthesis system. Cetrimonium nitrate was also used to template silica in a catalyst free system. X-ray diffraction of the catalyst free synthesis product showed the remnants of a structure that was likely destroyed during synthesis. X-ray data also indicated that calcination decreases d-spacing and causes peak broadening; while methanol-based removal at both room temperature and in a soxhlet extractor completely degrades the ordered structure. These results provide an understanding of how cetrimonium nitrate behaves as a template for mesoporous silica and how different surfactant removal techniques impact structure. Results also indicate that cetrimonium nitrate has the potential to be a self-catalyzing template which will be an interesting topic for future research.