Preparation of mesoporous silica nanoflakes and nanospheres with perpendicular pore channels

Silica nanoflakes and nanospheres with perpendicular pore channels are attractive due to their potential applications. Herein, the nanoflakes were prepared using the self-assemblies of a chiral low-molecular-weight amphiphile, L-18Ala4PyBr, as the templates; and nanospheres were prepared using this amphiphile and cyclohexane as a co-structure-directing agent. By gradually increasing the bridging alkylene chain length of L-18Ala4PyBr, amphiphiles L-18Ala6PyBr and L-18Ala11PyBr were synthesized. Nanoflakes with perpendicular pore channels and nanoworms with horizontal pore channels were prepared using L-18Ala6PyBr and L-18Ala11PyBr, respectively. The hydrophobic association of the bridging alkylene chains should play an important role in controlling the morphologies and pore architectures of the mesoporous silicas.