Preparation and magnetic performance of the magnetic fluid stabilized by bi-surfactant

A stable poly-alpha olefin oil based magnetic fluid of bilayer surfactant coated (oleic acid and succinimide) Fe3O4 nanoparticles was prepared by a using phase transfer method. The bilayer surfactant-coated magnetic particles are characterized by Fourier-transform infrared spectroscopy, the result shows that the Fe3O4 nanoparticles are coated by oleic acid, and the bilayer surfactant succinimide wraps the oleic acid coated Fe3O4 nanoparticles. Transmission electron microscopy images indicate that the dispersibility of the bilayer coated Fe3O4 nanoparticles is better than that of the uncoated ones. Vibrating sample magnetometer measurement confirms that both the coated and uncoated Fe3O4 nanoparticles are super-paramagnetic. Stability measurements show the magnetic fluids prepared by bilayer coated Fe3O4 nanoparticles is nearly constant for 360 days at room temperature. - Highlights: ► The oleic acid coated Fe3O4 nanoparticles are functionalized with polyisobutylene succinimide. ► The poly alpha olefin oil based magnetic fluid is obtained by phase-transfer method. ► The magnetic fluid is stable and superparamagnetic. ► The magnetic fluid exhibits well oil disperse characteristic. ► The magnetic fluid can be widely used in loudspeaker