超小型Fe3O4/Au纳米复合微粒的制备与表征

用反向微乳液法成功制备了超小型Fe3O4/Au磁性纳米复合微粒,并利用3-巯基丙酸将复合微粒直接从微乳液分离到有机溶剂中.用UV-Vis、VSM和TEM对产物进行了鉴定与表征,结果表明复合微粒分散良好,平均粒径为6.7nm,饱和磁化强度为9.7A·m2/kg.

Preparation and character of ultrasmall Fe3O4/Au nanoparticles

The well-dispersed gold-coated nanoparticles with magnetic Fe_3O_4 core were synthesized in quaternary CTAB (cetyltrimethylammonium bromide)/octane/butanol/water reverse micelles. In our present protocol, aqueous Fe_3O_4 nanoparticles were introduced into water droplets directly as nucleation centers for the subsequent formation of metallic shell via NaBH_4 reduction of Au~(3+) ions on their surfaces. 3-mercaptopropionic acid (MPA) was chosen to play roles of separating nanoparticles from destroyed reverse micelles system and stabilizing the as-prepared Fe_3O_4/Au nanoparticles in organic media. Different concentration of Au~(3+) ions were used to coat Fe_3O_4 nanoparticles. According to the TEM images, 0.1mol/L Au~(3+)and 10mmol/L magnetic fluid are the best choices for the coating. TEM images show that these MPA-capped core-shell structured nanoparticles are well dispersed and the mean particle size was about 6.7nm.