| Summary: | 碩士 === 國立成功大學 === 化學系碩博士班 === 94 === Understanding the growth mechanism of the organic-inorganic hybrids is intrinsically important for the synthesis of the mesoporous
materials. In the beginning of developing the synthetic methods of themesoporous silica, most of researcher focused on the preparation of
mesoporous silica with different mesostructures and improved framework stability. Based on the silica chemistry and well control the interaction
between the silica and surfactants, the mesoporous silica crystals in various morphologies have been obtained.
In this thesis, we use a ternary-surfactant system (C8TMAB-SDS-F127) as the template to synthesize the SBA-16 mesoporous silica crystals in an acidic silicate solution. At the isoelectric point of silica (pH » 2.0), the silica condensation rate is restively slowest
and the interaction between surfactant and silica species is weakly hydrogen bonding. Therefore, the surfactant and silica species can self-assemble slowly to from micron-sized SBA-16 mesoporous silica crystals. In addition, we studied in detail of the experimental factors such as the ratio of the cationic/anionic/F127, water content, concentration of silica species, pH value and the applying flow to find the optimum conditions and chemical components for the synthesis of high-quality SBA-16 mesoporous silica crystals.
Under the same synthetic condition (pH » 2.0), the hydrophobic phenol-formaldehyde (PF) resin can also be used to replace the C8TMAB-SDS catanionic surfactant. After a well-blending with F127,the well-identified SBA-16 mesoporous silica crystals were prepared by
the template of PF-F127 polymer blend. Moreover, we also studied the effect of the PF/F127 ratio, water content and concentration of silica species on the crystals morphology of the PF-F127 templated SBA-16 mesoporous silicas.
In order to obtain newly spectacular morphologies (like the diatoms in nature), we tried to use other surfactant mixtures. Here, two successful examples were illustrated. 1. The vesicle-like mesoporous silica were obtained with a fast silicification of C10TMAB-SDS-F127 template at pH » 5.0; 2. The fan-like mesoporous silica were prepared with the template of C14TMAB-SDS binary surfactant and then slow silicification at pH » 2.0.
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