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采用无皂乳液聚合法制备了Fe3O4/P(N-异丙基丙烯酰胺-共-丙烯酰胺)[P(NIPAAm-co-Am)]温敏磁性复合粒子,分别采用透射电镜(TEM),振动磁强仪(VSM)和动态激光散射仪(DLS)对复合粒子进行表征,并着重研究了复合粒子在交变磁场作用下的磁热性能。结果表明,Fe3O4纳米粒子表面包裹了一层P(NIPAAm-co-Am)温敏性聚合物,其最低临界溶解温度(LCST)约为40℃,利用磁性粒子在交变磁场下的磁热性能可使复合粒子的温度升高至LCST以上,可触发复合粒子发生体积收缩。另外,复合粒子在交变磁场下的磁热性能可通过改变磁性粒子的浓度或调节磁场来调控。
The temperature-sensitive magnetic composite particles of Fe3O4 / P (N-isopropylacrylamide-co-acrylamide) [P (NIPAAm-co-Am)] were prepared by soap-free emulsion polymerization. The magnetoresistance (VSM) and dynamic laser light scattering (DLS) were used to characterize the composite particles. The magnetocaloric properties of the composite particles under alternating magnetic field were studied. The results showed that the surface of Fe3O4 nanoparticles coated with a layer of P (NIPAAm-co-Am) temperature-sensitive polymer, the lowest critical solution temperature (LCST) of about 40 ℃, the use of magnetic particles in the magnetic field under alternating magnetic properties The temperature of the composite particles can be increased to above LCST, which can trigger the volume shrinkage of the composite particles. In addition, the magnetocaloric properties of composite particles under alternating magnetic field can be controlled by changing the concentration of magnetic particles or adjusting the magnetic field.