Self-assembled monolayer coatings on nanosized magnetic particles using 16-mercaptohexadecanoic acid

Abolaamphiphile, 16-mercaptohexadecanoic acid (MHA), was deposited on nanosized magnetic particles (gamma-Fe2O3) using a self-assembly method. The coated particles were characterized using X-ray photoelectron spectroscopy(XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The molecular orientation of surfactant on the surface was inferred from critical surface tension values determined by film notation and confirmed by infrared spectrum. Under the experimental conditions, MHA anchors onto the gamma-Fe2O3 surface by chemical bonding between the carboxylate head group and iron on the surface, leaving the thio or disulfide groups reactive. The self-assembled MHA film on gamma-Fe2O3 is immobilized and resistant to acid and base attack. The potential applications of the fabricated magnetic particles in biological cell separation and gold recovery are discussed.