Abstract
Because of the superparamagnetic property of iron oxide nanoparticles, more and more research groups were interested in the magnetic nanoparticles whether in fundamental or technological applications. And also the advantage of small size, iron oxide nanoparticles can be applied in human bodies. Nanoparticles were combined to bio-compatible compounds in recent researches, and by the lock-key character, magnetic nanoparticles can coordinate with specific materials. Then, when putting an external magnetic field, magnetic particles can be considered as a tracer. The Severe aggregation of iron oxide nanoparticles has always been a problem for practical uses, so the purpose of this thesis is to reduce the aggregation phenomenon of particles by surface modification. Particles with an average size of 6~8nm can be obtained by wet chemical method, and monolayer and bilayer made of lauric acid and decanoic acid were both modified on the surface of particles as a protective layer. IR microscope and thermal gravimetric analysis (TGA) were used to identify the existence of monolayer and bilayer. Besides, PDA molecules with chromism character were also modified outer particles. They were not only a protective layer, but also a sensor that can examine the bonding between PDA molecules and specific molecules through the change of the color of PDA. In the same way, IR and TGA were used to identify the surface modification, and UV microscope was also used to present the chromism character of PDA molecules.