5. Conclusion
SiCl4 was used as a new cheaper precursor to successfully produce spherical silica in two kinds of reverse micro emulsion systems in this paper. In NP-5/cyclohexane/deionized water micro emulsion system, the particles with mean particle size of 5.74 nm were obtained when the water and SiCl4 mole ratio was 4. In NP-5/heptane/deionized water system, the particles with mean particle size of 22.8 nm were produced when the water and SiCl4 mole ratio was 10. A decreased tendency for silica particles agglomeration could be achieved by using the smaller mole ratio. The silica prepared by these two systems was amorphous silica, and the phase structure of silica prepared from the different micro emulsion systems was similar; the residue organic molecules in the sample can be removed completely from the silica through 600 °C treatment according to the IR result.