Fabrication of hollow silica spheres in an ionic liquid microemulsion

Hollow silica spheres have been successfully synthesized by using the ionic liquid microemulsion droplets as the template. The morphology and microstructures of the silica spheres were investigated by scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), and Nitrogen adsorption-desorption measurements. The obtained images showed that the average size of the silica spheres was almost between 150 and 300 nm. The Nitrogen adsorption-desorption investigation on the silica spheres indicated the amorphous structure on the interface. Both of these two results provide us new insights into this novel template and hollow silica spheres were for the first time prepared free of additional acid and alkali conditions. The possible mechanism for the formation of silica spheres has been put forward and discussed in details.