Abstract：One-step feeding method sol-gel method was applied to prepare monodisperse silica microspheres. Dissolving in a mixture of ethyl alcohol, tetraethoxysilane (TEOS) and ammonia were selected as silicon source and catalyst, respectively. Fixing the reaction time, laser particle analyzer and transmission electron microscope were employed in finding out the influence of reaction conditions on the particle size and morphology of silica microsphere. On the basis of the optimum concentration TEOSand mass ratio of H₂O to TEOS being determined, the growth tendency of SiO₂ microsphere under different concentrations of ammonium hydroxide was detected. The results indicated that when fixing the reaction time to 5 h, the particle size of silica microsphere exhibited an uptrend with the increase of concentration of ammonia and mass ratio of H₂O to TEOS; while with the concentration of TEOS rising, the particle size went up first with a declining trend followed; the optimum sphericity of silica microspheres was obtained under the experimental conditions of ammonia concentration, TEOS concentration and mass ratio of H₂O to TEOS being set as 1.5 mol/L, 0.2 mol/L and80, respectively. The ripening time of silica microsphere was remarkably shortened by ammonia concentration rising, the shortest ripening time could reach to 2 h under the ammonia concentration 1.5 mol/L. Prolonging the reaction time to 14 h, the maximum particle size of microsphere, i.e. 411 nm, was obtained under the low ammonia concentration.

Keywords：silicon dioxide microsphere; particle size distribution; particle morphology; growth tendency