【摘要】 单分散纳米氧化硅颗粒被广泛应用于建筑、日化、航天、催化以及半导体等领域。制备纳米氧化硅颗粒需要经历成核和生长两个过程，其中成核过程是决定纳米颗粒球形度、集中度、颗粒形貌的基础。因此研究成核过程对整个反应和最终产品有着重要的意义。本工作以水玻璃为原料采用离子交换法制备纳米氧化硅颗粒，对硅酸浓度、单体添加速度以及颗粒成核中的形貌进行了细致的研究。结果发现，硅酸的适宜浓度为5%(质量分数);单体的添加时间宜维持在10 h;最终的颗粒粒径为21.8 nm。成核初期溶液中没有单分散的晶核，只存在无定形和相互交联的网状结构硅胶。以本工作确定的原料浓度和添加时间能够制备出单分散、球形度好的纳米氧化硅晶核，为后期颗粒的均匀生长提供重要的先决条件。更多还原

【Abstract】 Monodispersed silica nanoparticles are widely used in the fields of construction, daily chemistry, aerospace, catalysis and semiconductor. The preparation of silica nanoparticles includes two processes of nucleation and growth. The nucleation process is the foundation of spheri-city, uniformity and morphology of the silica nanoparticles, so the study of nucleation process is of great significance to the synthesis and the final products. In this work, the silica nanoparticles were prepared by the ion exchange method with the water glass as material. The concentration of the silicic acid, the addition rate of the monomer and the morphology of the particle during the nucleation process were stu-died in detail. The results show that the appropriate concentration of silicic acid is 5 wt% and the addition time should be 10 h. Final size of silica nanoparticle under this condition is 21.8 nm. In the early stage of nucleation, there is no monodispersed nucleus, only silica gel with cross-linked network structure exis-ting. Monodispersed and spherical silica nuclei can be prepared with the concentration of silica acid and addition time, which provides the critical condition for the uniform growth of particles in the next stage.更多还原