关键词: 油酸钠, Fe₃O₄, 纳米粒子, 表面改性

Abstract: Sodium oleate was used as surface modification agent to modify Fe₃O₄ nanoparticles prepared in high temperature organic solution. Fe₃O₄ nanoparticles were transferred from organic phase to aqueous solution by the van der Waals interaction between the long aliphatic chain of oleate anion and the hydrophobic groups in the surface of Fe₃ O₄ nanoparticles. Effects of concentration of sodium oleate, pH and temperature on surface modification of Fe₃O₄ nanoparticles were investigated. Mossbauer spectroscopy, Transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy were used to characterize samples before and after modification. The results show that the method is effective in ransferring Fe₃O₄ nanoparticles from organic phase to aqueous solution. The ratio of Fe₃O₄ anoparticles transferred from organic phase is as high as 86％ and the content of ransferred Fe₃O₄ nanoparticles in aqueous solution is 10.5mg·mL^-1 on condition that the concertration of sodium oleate solution is 3mmol/L, the content of Fe₃O₄ nanoparticles in n-hexane is 12.28mg·mL^-1, pH is 8.6,temperature is 60℃, respectively. The surface modified Fe₃O₄ nanoparticles with low concentration in aqueous solution can stably disperse in aqueous solution for a long time.

Key words: sodium oleate, Fe₃O₄, nanoparticles, surface modification