Synthesis and Magnetic Properties of Hydrophilic and Hydrophobic Hybrid Nanocomposite

The magnetic properties of hydrophilic hybrid nanocomposite (multi-walled carbon nanotubes modified with magnetite nanoparticles) and hydrophobic hybrid nanocomposite (multi-walled carbon nanotubes modified with magnetite nanoparticles coated with oleic acid) were studied in the temperature range of 2-290 K and magnetic field up to 6 T. Both samples were characterized morphologically, thermally, and magnetically. Magnetite nanoparticles bounded to multi-walled carbon nanotubes were close to spherical and the particle size was distributed from 10 to 25 nm, as observed by transmission electron microscopy. The thermogravimetric analysis of the hydrophobic hybrid nanocomposite pointed out bounding the oleic acid on the nanoparticles. The hydrophobic, as well as the hydrophilic nanoparticles exhibited a typical superparamagnetic behavior at room temperature. The magnetic measurements at 2 K indicated ferromagnetic behavior. The value of coercivity of hydrophilic or hydrophobic nanocomposites at 2 K were 0.018 T and 0.037 T, respectively. It was found that the presence of the bounded oleic acid results in the decrease in the magnetization of saturation, as compared to the hydrophilic nanocomposite.