摘要：采用溶胶凝胶法一步加料制备了单分散二氧化硅微球。制备过程选用正硅酸乙酯 (TEOS) 硅源, 氨为催化剂, 乙醇-水混合溶液为溶剂。固定反应时间, 通过激光粒度仪和透射电镜研究多个反应条件对二氧化硅微球粒径和形态的影响;在确定TEOS浓度、水与TEOS物质量比这2个反应条件的基础上, 对不同氨浓度下二氧化硅微球的生长趋势进行研究。实验结果表明:当反应时间为5 h时, 二氧化硅微球粒径随氨浓度及水与TEOS物质量比的升高而增大, 随着TEOS浓度的升高呈先增大后减小的趋势, 二氧化硅微球在氨浓度为1.5 mol/L、TEOS浓度为0.2 mol/L、水与TEOS物质量比为80:1的实验条件下取得最佳球形度;升高氨浓度可有效缩短二氧化硅微球熟化时间, 在氨浓度1.5 mol/L实验条件下, 熟化成型时间缩短至2 h;延长反应时间至14 h, 在较低氨浓度的实验条件下得到二氧化硅微球的平均粒径为411 nm。
关键词：二氧化硅微球；粒度分布；颗粒形态；生长趋势
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
