| Mesoprous materials have opened many new possibilities for applications in catalysis, separation, optics, electrics, magnetism and nanosciences due to their large, controllable, pore sizes and high surface areas. Since 1992, a variety of silica mesoporous materials (such as M41S,SBA-X (1-16),HMS and MSU) with different structures (cubic, hexagonal , lemellar and disorder) have been prepared by using the cooperative-organization of ionic surfactants and ionic silica species in water. Various structured mesoporous molecular sieves possess different physical properties, which promote material scientist to take great efforts to exploit new synthesis route to obtain novel mesoporous material structure.Surfactant molecules play a key role in directing the formation of the inorganic mesostructure from soluble mineral species. The size, shape and charge of the surfactant head group play a critical factor in the aggregation shape and properties of the surfactant solution, which will direct effect the interaction between the organic and the inorganic precursor. The idea for synthesizing mesoporous materials with novel structure and functional properties promote us to design carefully and synthesize the surfactant with novel structure and properties.The current contribution concerns the synthesis of novel structure mesoporous materials templated by novel multi-head group quaternary ammonium surfactant. Combining the organic chemistry, the concepts of sol-gel chemistry, colloid science and supramolecular self-assembly, tri-head group quaternary ammonium surfactants and tetra-head group quaternary ammonium surfactant with high charged density have been successfully designed and synthesized in our laboratory. And a series of new mesoporous materials with different structures (include cubic, hexagonal and tetragonal mesophase) have also successfully been synthesized using the above quaternary ammonium surfactant as structure directing agent. In addition, when the template stratagem was extended to the synthesis of non-silica mesotructured materials, high ordered cubic zirconium oxide sulfate and zirconium oxophosphate with Pm3n symmetry were obtained.In Chapter 2, based on the introduction of the phase behavior in the surfactant solution and combining the synthesis mechanism of the mesoporous molecule sieves. We reported the design and synthesis of tri-head group quaternary ammonium surfactant (Cn-s-m-1), which are a kind of multi-charged cationic surfactant with three head groups separated by different methylene chains and a variable length hydrophobic tail, thus, high charged amphiphile with different hydrophobic chain length include C14-2-3-1, C16-2-3-1, C18-2-3-1, C22-2-3-1 and with different spacer include C18-3-3-1 and C18-3-4-1 were obtained. In addition, C18-2-3-1 was purified by recrystallization and was characterized by 1H NMR and element analysis. Other intermediate such as C14-2,C16-2,C22-2 and C18-3 were also characterized by 1H NMR.In Chapter 3. We reported the synthesis of the novel mesoporous silica templated by tri-head group quaternary ammonium surfactant (C18-2-3-1) under basic condition. XRD and TEM confirmed that the novel mesoporous silica has a diamonded face centered cubic structure with Fd3m symmetry, which was first reported up to date. Physical properties include BET surface area, BJH pore volume and pore size have been determined by N2 adsorption-desorption. In addition, different reaction parameters have been further studied on the synthesis of cubic mesoporous silica.In Chaper 4. The template effects of a series of tri-head group quaternary ammonium amphiphiles on the synthesis of the mesoporous silica under different media have been discussed systematically: mesoporous silica with different structure have been obtained using C18-2-3-1 as structure directing agent under basic (include organic base and inorganic base) and acidic (include HCl, HNO3, HBr and H2SO4) conditions. Novel mesoporous silica with unknown structure synthesized in the TMAOH media was discussed by XRD...
|
PDF Full Text Request