Magnetic monolayer film of oleic acid-stabilized Fe3O4 particles fabricated via Langmuir-Blodgett technique

The fabrication of monolayer film of surfactant-stabilized magnetic Fe₃O₄ particles with a size range of 90–150 nm via the Langmuir-Blodgett method is described in this paper. Magnetic Fe₃O₄ particles coated with oleic acid were firstly synthesized by a hydrothermal process, and then the particles were dispersed into chloroform. After that, the Fe₃O₄ suspension was spread to the interface of air/water and transferred to the glass surface. The formation of the Langmuir monolayer of oleic acid-stabilized Fe₃O₄ particles at air/water interface was revealed with the pressure-area isotherm curves. The results of the surface pressure-area isotherm and Atomic Force Microscopy showed that this film is a well compressed monolayer of 2-dimensional Fe₃O₄ particles assembly. Magnetometry results showed that the saturation magnetization of Fe₃O₄ magnetic particles is 86.1 A·m²/kg at room temperature with an applied field of 0.6 T.