表面活性剂对磁流体稳定性及外层包覆结构的影响

采用化学共沉淀法制备粒径分布均匀的纳米Fe3O4颗粒,用油酸钠和聚乙二醇4000(PEG4000)对纳米Fe3O4颗粒进行表面修饰,制得分散稳定的纳米Fe3O4磁流体,通过电动电位(Zeta电位)、粒径测试、离心沉淀、红外光谱分析(FT-IR)和热分析(TG)对修饰后的纳米Fe3O4颗粒进行了稳定性能评价与结构表征。结果表明,油酸钠与纳米Fe3O4颗粒存在两种不同类型的化学键作用;增大油酸钠加入量不会改变Fe3O4颗粒表面包覆结构,但是,其在纳米Fe3O4颗粒表面的吸附量呈先增加后降低的趋势;PEG4000物理吸附于油酸钠包覆的纳米Fe3O4颗粒表面,PEG4000的加入会进一步提高磁流体的稳定性。

Influence of Surfactants on the Stability and Coated Structures of Magnetic Fluids

A uniform size of Fe3O4 nanoparticles were prepared by the chemical co-precipitation method,the Fe3O4 nanoparticles were modified by sodium oleate and PEG4000.The modified Fe3O4 nanoparticles were characte-rized and studied by various methods such as Zeta potential,particle size,centrifuge precipitation,FT-IR and TG.The results indicate that there are two different chemical bonds between sodium oleate and Fe3O4 nanoparticles,the surface structure of Fe3O4 nanoparticles do not change with the addition amount of sodium oleate,which causes the amount of the absorption of sodium oleate on the surface of Fe3O4 nanoparticles first increase and then reduce when it reaches a certain value;PEG4000,which is physically adsorbed on the surface of sodium oleate coated Fe3O4 nanoparticles,could improve the stability of nano-scale Fe3O4 magnetic fluids.