| Summary: | 碩士 === 東海大學 === 化學工程與材料工程學系 === 105 === Gradually, the magnetic nanoparticles have been noticed and widely studied in science community. The magnetic nanoparticles were used for functional materials applications such as magnetic media storage, magnetic resonance agent, drug release, and catalyst…etc. Nanoparticles of different sizes were applied for different purposes. There were many ways to prepare γ-Fe2O3 magnetic nanoparticles. Chemical pyrolysis was used to prepare γ-Fe2O3 magnetic nanoparticles in this research. The γ-Fe2O3 magnetic nanoparticles of different sizes were prepared by changing the amounts of oleic acid, Fe(CO)5, and octyl ether. Oil-soluble nanoparticles were converted to water-soluble nanoparticles by using α-cyclodextrin as the phase transformation agent.
Structures of γ-Fe2O3 magnetic nanoparticles were examined by XRD. The structures of oil-soluble nanoparticles and those of water-soluble nanoparticles were the same. Sizes of nanoparticles were examined by TEM. The size of standard particle was 3 nm. Particle sizes of γ-Fe2O3 magnetic nanoparticles increased by changing the amounts of Fe(CO)5 , oleic acid, and octyl ether. Sizes of prepared nanoparticles were between 4 and 20 nm. The particle of maximum size was prepared by doubling the amount of Fe(CO)5. The maximum size of nanoparticle was 20 nm in this research. Magnetic properties of γ-Fe2O3 nanoparticles were detected by VSM. Within the magnetic field range of -10 to 10 kOe, the effects of partical size and phase transformation on maximum magnetization and coercivity were unobvious. The values of maximum magnetization and coercivity remained at the same order, respectively.
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