单分散纳米介孔二氧化硅的制备

Preparation of monodisperse nanosized mesoporous silica

在温和碱性条件下,以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,三嵌段共聚物F127为助剂,制备出粒径为60～80 nm的单分散纳米介孔二氧化硅MCM-41.研究了F127的用量对介孔结构和纳米粒子分散性的影响.结果表明,适量的非离子表面活性剂F127具有助模板剂的作用,可以有效地提高纳米介孔粉体的有序性;过量的F127阻碍六方介孔相的形成。降低样品的有序性.F127与十六烷基三甲基溴化铵的摩尔比在0.04～0.08范围内,可以得到有序性好、孔径均一和孔隙率大的单分散纳米介孔二氧化硅MCM-41。

Using the cationic surfactant-cetyltrirnethylammoniurn bromide (CTAB) as template, tetraethyl orthosilicate (TEOS) as silica source and nonionic surfactant-triblock copolymer F127 as dispersant, the monodisperse nanosized mesoporous siliceous MCM-41 was prepared by room temperatural synthesis method in basic media. The samples were characterized by techniques such as XRD, TEM, HRTEM, SEM, IR and N2 physisorption. In addition, the influences of different molar ratios of F127 to CTAB on mesoporous crystalline structure, surface structure, pore size distribution and the dispersity of nanosized mesoporous siliceous MCM-41 were also systemically studied. The results show that a suitable amount of F127 can greatly improve the ordered structure of pore array, while an excessive amount of F127 will destroy the ordered structure. When the molar ratio of F127 to CTAB was ranged from 0.04 to 0.08, the synthesized samples were nanoparticle, monodispersed, single-pore distributed, huge pore volume and highly ordered mesoporous structure.