Yan Feng, Li Jun, Fu Rong, Lu Ziyang, Yang Wensheng
Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Changchun 130012, PR China.
J Nanosci Nanotechnol. 2009 Oct;9(10):5874-9. doi: 10.1166/jnn.2009.1240.
Fe3O4/poly(St-co-MPS) particles were prepared by encapsulation of Fe3O4 nanoparticles into copolymers of styrene (St) and 3-trimethoxysilylpropylmethacrylate (MPS) (poly(St-co-MPS)) prepared by miniemulsion copolymerization. It is found that the structure of the Fe3O4/poly(St-co-MPS)/SiO2 composite particles prepared by direct silica deposition on surface of the Fe3O4/poly(St-co-MPS) particles is dependent on the volume fraction of MPS used in the copolymerization. It is identified that the surface of the Fe3O4/poly(St-co-MPS) particles becomes more negatively charged with increased volume fraction of MPS used in the copolymerization, attributed to the increased amount of the silanol groups on the particles surface. Introduction of silanol groups on the particle surface is effective to improve the dispersibility of the Fe3O4/poly(St-co-MPS) particles and their compatibility with silica, allowing the facile preparation of Fe3O4/poly(St-co-MPS)/SiO2 composite particles with defined core-shell structure. The as-prepared Fe3O4/poly(St-co-MPS)/SiO2 composite particles show high magnetization, for example, saturation magnetization of the particles with average size of 140 nm and 6 nm silica shell is as high as 45 emu/g at 300 K.
通过将Fe3O4纳米颗粒封装到由细乳液共聚制备的苯乙烯（St）和甲基丙烯酸3-三甲氧基硅丙酯（MPS）的共聚物（聚（St-co-MPS））中来制备Fe3O4/聚（St-co-MPS）颗粒。研究发现，通过在Fe3O4/聚（St-co-MPS）颗粒表面直接沉积二氧化硅制备的Fe3O4/聚（St-co-MPS）/SiO2复合颗粒的结构取决于共聚中使用的MPS的体积分数。已确定，随着共聚中使用的MPS体积分数增加，Fe3O4/聚（St-co-MPS）颗粒表面带负电荷增多，这归因于颗粒表面硅醇基团数量的增加。在颗粒表面引入硅醇基团有效地改善了Fe3O4/聚（St-co-MPS）颗粒的分散性及其与二氧化硅的相容性，从而能够轻松制备具有明确核壳结构的Fe3O4/聚（St-co-MPS）/SiO2复合颗粒。所制备的Fe3O4/聚（St-co-MPS）/SiO2复合颗粒显示出高磁化强度，例如，平均粒径为140 nm且二氧化硅壳层厚度为6 nm的颗粒在300 K时的饱和磁化强度高达45 emu/g。
