超声乳化法制备纳米Fe_3O_4磁性颗粒及壳聚糖表面改性

Preparation of Fe_3O_4 magnetic nanoparticles by ultrasonic emulsification and research of magnetic fluids with chitosan modification

采用超声乳化法制备纳米Fe3O4磁性颗粒,以壳聚糖作为表面活性剂,制备具有生物亲和性的水基Fe3O4磁流体.研究了Fe2+/Fe3+摩尔比、超声时间和表面活性剂用量对磁流体性能的影响.结果表明:当Fe2+/Fe3+摩尔比为1:1·5,滴加氨水时反应温度为70℃时,可制备理想纳米Fe3O4磁性颗粒;超声时间为7·5min左右,质量分数1%的壳聚糖溶液体积占FeO溶液总体积的50%时,有利于壳聚糖分子的包覆,使磁流体具有较高的比饱和磁化强度及稳定性.

Fe3O4 magnetic nanoparticles were prepared by means of ultrasonic emulsification and then the Fe3O4 magnetic fluid was made by dispersing these particles into water with chitosan as surfactants.The influences of the molar ratio of Fe2＋ to Fe3＋,ultrasonic time and the amount of chitosan on the magnetic properties of the magnetic fluid were investigated.The results show that ideal Fe3O4 magnetic nanoparticles can be obtained under the condition that the molar ratio of Fe2＋ to Fe3＋ is 1：1.5 and the reaction temperature is 70 ℃ when dropping ammonia.The prepared magnetic fluid has high specific saturation magnetization and stability when the volume of the 1% chitosan solution is 50% as large as the total volume of the mixed Fe3O4 solution and the ultrasonic time after dropping chitosan is 7.5 min,which are in favor of coating the magnetic particles with chitosan.