Fabrication of Uniform Hierarchical Mesoporous Wrinkled Silica Nanoparticles and Their Applications: Chemical Mechanical Planarization, Solar Cell, and Electrorheological Fluid

Abstract

Mesoporous silica nanomaterials have received much attention due to their dramatic increased surface to volume ratio. These porous structures have been used extensively in a variety of applications such as catalyst supporters, adsorption, separation, drug delivery, electrodes, and hard templates for fabrication of nanocomposites due to their unique features. Among various structures of mesoporous silica nanomaterials, spherical mesoporous silica nanoparticles have attracted much attention because they provide excellent pore accessibility and smooth molecular diffusion. Therefore, various methods for the fabrication of spherical mesoporous silica nanoparticles with a range of pore structure types have been reported, and have contributed to the development of fields such as packing materials for chromatography, drug delivery, cosmetics, and adsorption. However, despite the variety of methods for preparing spherical mesoporous silica nanoparticles, it should be still required to develop fabrication methods of spherical mesoporous silica nanoparticles with uniformity and high yields. This dissertation introduces a method for fabricating uniform hierarchical mesoporous wrinkled silica nanoparticles. Furthermore, formation mechanism of the uniform spherical mesoporous silica naoparitcles was discussed by investigating the factors affecting the particle size and pore size of the naoparitcles. Thus, a complete method for high-yield production of uniform hierarchical mesoporous wrinkled silica nanoparticles with tunable particle size and pore size is provided. The prepared uniform mesoporous silica nanoparticles manifested better performance than non-porous silica nanoparticles of the same size in applications of abrasives in chemical mechanical planarization, scattering materials in dye sensitized solar cells, and hard templates for fabricating nanocomposite of ER fluids, demonstrating the superiority of the mesoporous structure. This dissertation suggests that silica nanoparticles with mesoporous structure offer the potential for performance enhancement in applications where non-porous silica spheres are currently used.