全氟聚醚油基磁性液体分散稳定性研究

Research on the dispersion stability of perfluoropolyether oil based ferrofluid

通过化学共沉淀法制备纳米磁性颗粒,由表面活性剂包覆后分散于全氟聚醚油中,得到具有优异性能的磁性液体。通过X射线衍射仪(XRD)、红外光谱仪(FTIR)、透射电镜(TEM)、振动样品磁强计(VSM)等表征颗粒的微观结构、包覆效果及表面活性剂用量、颗粒含量、基液粘度、磁场作用对磁性液体分散稳定性的影响。结果表明,颗粒的粒径为10~20 nm,颗粒为类超顺磁性材料,能够被表面活性剂氟醚酸化学包覆。随氟醚酸用量增多,包覆颗粒由红棕色粉末状逐渐变为黑色粘稠物,磁性液体的分散稳定性先升高后降低;随颗粒含量减少及基液粘度增大,磁性液体的分散稳定性有升高趋势;磁场作用使部分团簇颗粒发生沉降。制备出具有较高分散稳定性的氟醚油基磁性液体,有利于提升其在密封、润滑、减振等领域中的应用效果。

The magnetic nanoparticles were prepared via chemical co-precipitation method,which were coated by surfactants and then dispersed in perfluoropolyether oil(PFPE-oil),and the ferrofluids with superior performances were obtained.The X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),transmission electron microscopy(TEM)and vibrating sample magnetometer(VSM),etc.were used to characterize the micro-structures and the coated effect of particles,and to characterize the effects of surfactant dosage,nanoparticle concentration,the viscosity of base liquids and magnetic field on the dispersion stability of ferrofluids.The results show that the average size range of particles is from 10 nm to 20 nm,the nanoparticles are like-superparamagnetic materials and could be chemically coated by perfluoropolyether carboxylic acid(PFPE-acid).With increasing PFPE-acids dosage,the coated reddish-brown particles change to be dark sticky materials and the dispersion stability of the ferrofluid increases firstly and then reduces.With increasing nanoparticles concentration and the viscosity of base liquids,the dispersion stability of the ferrofluid has the tendency of increasing.The magnetic field makes the parts of agglomerated particles settle.The synthesized PFPE-oil based ferrofluids have well dispersion stability,which will improve their application performances,such as in sealing,lubrication,absorbers,etc.