| The preparation and applicaitons of chiral mesoporous silicas and hollow silica spheres were studied in this thesis. Firstly, helical mesoporous silica nanostructures were prepared through a templating approach, whose morphologies and pore architectures were controlled by tuning the reaction conditions such as concentration, temperature and stirring rate. The obtained samples were characterized using field-emission electron microscopy, transmission electron microscopy (TEM), X-ray diffraction and nitrogen sorptions. These materials are pofentially applied for enantioseparation and asymmetric catalysis. Moreover, polyaniline and polypyrrole were prepared through oxidative polymerization within the porous channels by filling aniline or pyrrole. The composites for its unique properties can be used in various fields, including humidity sensors, electrorheological materials, and electrochemical capacitors. Secondly, mesoporous silica hollow spheres have been successfully synthesized using cetyltrimethylammonium bromide (CTAB) and2-(perfluoro-n-octyl)ethanol (PFOE) at mild conditions. The layers number of mesoporous silica hollow spheres increases with increasing the PFOE/CTAB molar ratio from0.2:1to0.7:1. TEM images taken after different reaction times indicated that the multilamellar vesicles served as the nucleate sites. The hollow spheres with large cavity and short mesochannels would have potential applications for catalysis, biomolecular encapsulation and targeted stimulative release of drugs. |
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