Interaction Mechanism between Fe3O4 Nanoparticles and Sodium 2-dodecylbenzenesulfonate

In the paper, the dispersion stability of Fe3O4 nanoparticles in water by ball milling with surfactant sodium 2-dodecylbenzenesulfonate (SDBS) was studied. The ball milling time as influence factor on the stability of magnetic fluid was investigated. Then, the nano-Fe3O4 magnetic fluid was prepared and characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), particle size analyzer, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results show that the best time of ball milling is about 5h. The stably dispersed Fe3O4 mean size is about 34.1 nm. SDBS is adsorbed on the surface of nanoparticles by chemical bonds. SDBS covers Fe3O4 nanoparticles through sulfonate group links. Then another SDBS continues to adsorb by physical forces to disperse stably in the water solution by the steric hindrance and electrostatic effect.