School of Public Health, Southeast University, Nanjing 210009, China.
J Biomed Nanotechnol. 2009 Oct;5(5):596-601. doi: 10.1166/jbn.2009.1065.
SiO2/(PMMA/Fe3O4) composite particles were prepared from linolenic acid (LA) instead of oleic acid (OA) modified Fe3O4 nanoparticles by miniemulsion polymerization. LA has three unsaturated double bonds with which it can polymerizate more easily than OA. And coating Fe3O4 with polymethyl methacrylate (PMMA) polymer beforehand can prevent magnetic nanoparticles from the aggregation that usually comes from the increasing of ionic strength during the hydrolyzation of tetraethoxysilane (TEOS) by the steric hindrance. Finally, the resulting PMMA/Fe3O4 nanoparticles were coated with silica, forming SiO2/(PMMA/Fe3O4) core-shell structure particles. The sizes of nanoparticles with core-shell structure were in the range from 300 to 600 nm. The nanoparticles were spherical particles and had consistent size. The result of magnetic measurement showed that the composite particles had superparamagnetic property.
采用亚油酸（LA）代替油酸（OA）改性的四氧化三铁纳米粒子，通过细乳液聚合制备了 SiO2/（PMMA/Fe3O4）复合粒子。LA 具有三个不饱和双键，使其比 OA 更容易聚合。并且，通过空间位阻作用，预先用聚甲基丙烯酸甲酯（PMMA）聚合物涂覆 Fe3O4，可以防止磁性纳米粒子在四乙氧基硅烷（TEOS）水解过程中由于离子强度增加而发生聚集。最后，用硅酸钠对得到的 PMMA/Fe3O4 纳米粒子进行包覆，形成 SiO2/（PMMA/Fe3O4）核壳结构粒子。核壳结构纳米粒子的粒径范围为 300-600nm。纳米粒子为球形，粒径均匀。磁性测量结果表明，复合粒子具有超顺磁性。
