Control The Mesoporous Silica Nanostructures Using Chiral Low-molecular-weight Molecules

Recently, the preparation of fascinating and improved mesostructured materials has attracted increasing attention for their widespread potential applications. Firstly, hollow silica spheres with holes in their shells were prepared. The L-16AlaPy6Br aggregates acted as the templates for the holes. By changing the reaction conditions, hollow silica spheres with fine vertical pore channels were also prepared using L-16AlaPy6Br. These artificial frustules are potentially applied for controlled release. Secondly, silica nanotubes with spring-like pore channels in the walls were prepared using the self-assemblies of L-16ValPy6Br as templates through a single-templating approach. Their pore architectures were simulated using 3D Studio MAX software. The TEM images taken after different reaction times indicated a cooperation mechanism. The results shown here offer us opportunities to create artificial frustules and other hierarchical porous metal oxides at nano-scales. Thirdly, mesoporous silica nanoparticles with rod-like pore channels inside and lamellar mesopores on the surfaces were prepared using the self-assemblies of L-16PheN(Et)3 as templates. Field-emission scanning electron microscopy images taken after different reaction times indicated that the lamellar mesopores were formed by merging rod-like micelles. Helical hierarchical porous nanofibers were obtained using n-octanol as a co-structure-directing agent. Fourthly, the morphologies and pore architectures of mesoporous silicas were controlled by tuning stirring rate. With increasing the stirring rate of the reaction mixture, silica nanotubes with coiled pore channels changed to linked nano-cocoons with coiled pore channels. Finally, some other silica nanostructures were controlled using the self-assemblies of some other amino acid derivates.