Thin films of mesoporous silica
The preparation of thin films of silica-surfactant mesostructured materials has been reported by several synthetic methods. The very first example on the preparation of silica-surfactant mesostructured materials as film was reported by us in 1994. Since then, there have been a huge number of publications on mesoporous silica films.
Example of monodispersed particles. In order to obtain a variety of well-defined particles, such approaches as homogeneous precipitation and emulsion polymerization have been utilized as solution phase syntheses. Figure 1 shows examples of monodispersed particles. In addition to the chemical design, process development is also useful, so that spray drying and pyrolysis, flow reactor syntheses, etc. have been utilized.
Core-Shell Particles of Mesoporous Silica
In addition to the deposition of mesoporous silica layer on macroscopically shaped solid supports, core-shell particles composed on mesoporous silica shell on small particles has attracted increasing interests. Here, some examples are introduced to show the structure and possibility of core-shell particle composed of mesoporous silica shell.
Spherical particles of silica and nanoporous silica
Among the monodispersed inorganic particles, spherical one is a promising material morphology for such applications as liquid crystal display spacers, photonic crystals and as a liquid chromatography stationary phase, depending on their size, composition and structure. The preparation of monodispersed spherical particles of silica with the size of several hundreds of nm to a few micron are one of the most famous examples of morphology controlled inorganic materials. In addition to pure silica, silica based hybrid have been synthesize as monodispersed spherical particles. Monodispersed nanoporous silica spherical particles were synthesized by using alkoxysilane as silica source and alkyltrimethylammonium halide surfactant as supramolecular template.
Flow reactor syntheses of inorganic particles
Schematic drawing of Flow reactor with Y type junction.
Flow reactors with the channel dimension ranging from micron to millimeter size deal with the flow of minute amounts of liquid or gas within the channels. Since the development of such flow reactors in the early 1990s, advances in the design, fabrication, and utilization of flow reactor devices have led many applications in pharmaceutical, biotechnology, and chemical industries. Such applications fine chemical synthesis, diagnosis, crystallization, combinatorial synthesis and high-throughput screening, rapid chemical analyses, have been reported so far. Flow reactors offer several advantages for the preparation of inorganic and hybrid particles as reliable and systematically controlled process. Thanks to the flow reactor, we have reported the preparation of well-defined silica, organosilica, titania, ziroconia particles containing surfactants. The transformation of the well-defined hybrid particles into porous solids were also reported. The set-up of flow reactor with Y type junction is schematically shown in Figure 2.