超小型Fe_3O_4/Au纳米复合微粒的制备与表征

Preparation and character of ultrasmall Fe_3O_4 /Au nanoparticles

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。

The well-dispersed gold-coated nanoparticles with magnetic Fe3O4 core were synthesized in quaternary CTAB (cetyltrimethylammonium bromide)/octane/butanol/water reverse micelles. In our present protocol, aqueous Fe3O4 nanoparticles were introduced into water droplets directly as nucleation centers for the subsequent formation of metallic shell via NaBH4 reduction of Au3+ 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 Fe3O4/Au nanoparticles in organic media. Different concentration of Au3+ ions were used to coat Fe3O4 nanoparticles. According to the TEM images, 0.1 mol/L Au3+ and 10 mmol/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 6.7 nm.