Synthesis of Mesoporous Silicas in Various Novel Morphologies Using Cationic-Anionic Binary Surfactant Mixtures

• Main Authors: Peng-TingLi, 李芃葶
• Other Authors: Hong-Ping Lin
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/72541830137841555983

碩士 === 國立成功大學 === 化學系 === 102 === Molecular self-assembly behavior generally existing in the living systems is the basis of complex biological structures. In this thesis, we mimic the biomineralization to fabricate mesoporous silica materials in various morphologies and mesostructures. Based on surfactant chemistry, it is known that there are many mesophases and morphologies existing in the mixture of cation-anionic surfactant (i.e. catanionic surfactant). Therefore, the catanionic surfactant in different cationic/anionic surfactant ratios can be used as a versatile template to synthesize the mesoporous silica with spectacular morphologies. Actually, the morphology of the resulted mesoporous silica is dependent on the synthetic conditions (such as temperature, molar ratio(R) of the anion/cation surfactant, silica source and water content). As the R value is set to be around 0.4, red cell-like mesoporous silica was synthesized at pH5.5 and 40℃. Interestingly, after hydrothermal treatment, the center part gets hollow, and the donut-shape mesoporous silica was formed instead. Similarly, as the R value decreased to be 0.2, dendrimer-like mesoporous silica spheres formed at pH8.0 and 40℃. Due to the alkaline reaction condition, it is suitable for preaparing nano-metal/mesoporous silica materials for advanced applications. To fabricate mesoporous silica helical fibers, the optimal R value is around 0.15 under a reaction condition at pH of 1.5 and 55℃. After hydrothermal treatment, the mesoporous silica helical hollow fibers were produced. Furthermore, a homogeneous mixture of the mesoporous silica helical fibers and liquid crystal can be used to assemble a smart window.