Synthesis of superparamagnetic carboxyl functional magnetite microspheres through polyol process

Superparamagnetic carboxyl functional magnetite microspheres were synthesized through polyol process.Urea was introduced to the polyol process as homogeneous precipitator to promote the hydrolyzation of ferric ions and accelerate the formation of magnetite microspheres.The amount of water added into the polyol process was carefully controlled to quantitatively investigate the water effect on the products and its mechanism was primarily interpreted.By gradually varying the amount of water from 120 to 360μl,the average size of the resulting microspheres was changed from about 360 to 250nm.The as-synthesized magnetite microspheres were superparamagnetic at room temperature and had high saturation magnetization over 70A·m2/kg.With high magnetism and carboxyl functional surface,the superparamagnetic magnetite microspheres will have good potential in biomedical applications.