采用溶剂热法,分别以FeCl3.6H2O和CoCl2.4H2O为铁源和钴源,二甘醇和二乙醇胺为溶剂和配位剂,制备了水溶性CoFe2O4纳米粒子。采用TEM、XRD、FTIR光谱、热重-差热分析等技术对所得纳米粒子进行表征,并研究了材料的磁学性质。结果表明,这种铁酸钴纳米粒子具有超顺磁性,饱和磁化强度Ms达53.2emu/g,其横向弛豫系数为r2为36.54 Fe mM-1s-1,纵向弛豫系数为r1为1.68 Fe mM-1s-1,可以作为T2加权磁共振成像对比剂。
In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.
