Synthesis and Formation Mechanisms of Silicon Dioxide Spherical Particles

The monodispersed silicon dioxide spherical particles were synthesized by sol-gel methods,tetraethoxysilane(TEOS) as silicon material,ammonia as catalyst and ethanol as solution in ester-alcohol-water system. In order to illuminate TEOS titration modes,reactant concentration and reaction temperature effects on size and morphology of SiO2,samples are tested by SEM,BET and FT-IR. The results show that TEOS titration step by step is propitious to round, monodisperse and compact SiO2 synthesis. Under condition of reaction temperature of 25 ℃,TEOS moore concentration of 0.12 mol/L,ammonia of 14.8 mol/L,deionized water,and the pH value controled between 9～12,monodispersed silica spheres 200～250 nm in diameter,diametical consistency about 0.5 and standard deviation 7.5% were obtained. The formation mechanisms of SiO2 under different reaction conditions were also discussed.