磁性Fe_3O_4-聚吡咯纳米微球的合成与表征

报道了具有核壳结构的Fe3O4 聚吡咯磁性纳米微球的合成方法和表征结果 .微球同时具有导电性和磁性能 .在优化的实验条件下 ,可得到饱和磁化强度为 2 3 4emu g ,矫顽力为 45 2Oe的磁性微球 .微球的导电性随着微球中Fe3O4含量的增加而下降 .微球的磁性能则随着Fe3O4含量的增加而增大 .Fe3O4磁流体的粒径和磁性聚吡咯微球的粒径均在纳米量级 .纳米Fe3O4粒子能够提高复合物的热性能 .实验表明 ,磁流体和聚吡咯之间存在着一定的相互作用 ,正是这种相互作用使磁性聚吡咯纳米微球的热稳定性提高 .

PREPARATION AND CHARACTERIZATION OF MAGNETIC Fe3O4- POLYPYRROLE NANOPARTICLES

A novel approach to synthesize core-shell nanoparticles with Fe 3O 4 as the magnetic core and PPY as the conducting shell was investigated.The Fe 3 O 4 na noparticles primarily prepared by precipitation-oxidation method,and the Fe 3 O 4-P PY nanoparticles with core-shell structure was synthesized via an in-situ polymer ization of pyrrole monomer in an aqueous solution containing well-dispersed Fe 3O 4 nanoparticles and surfactant NaBS.The particles are almost spherical wit h diameters ranging from 20～30?nm.These p articles are polydisperse and some of them agglomerated due to magneto-dipole i nteractions between particles.70% to 80% of the Fe 3O 4-PPY particles are ran ged from 30～40?nm in diameter.The core-shell structure of nanoparticles was e videnced by TEM observations. The Fe 3O 4 content was found to affect significantly both the conductivity an d the mag netization of the resulting PPY composites.When 9% Fe 3O 4 was incorporated i nto PPY,the conductivity of PPY composite was greatly reduced from 6.52×10 -3 to 1.9 4×10 -4?S/cm.Further increasing of Fe 3O 4 content from 8.2% to 28.2 wt%,resulted in slight reduction of the conductivity at room temperature.The decrease in con ductivity of Fe 3O 4-PPY composites with increasing Fe 3O 4 content was due to a decr ease in the doping degree,assigned as S/N ratio.The S/N ratios decrease from 0 . 34 to 0.19 with increasing Fe 3O 4 content from 0 to 28.2 %.The magnetic pr opert ies of the Fe 3O 4-PPY nanocomposites depend on the Fe 3O 4 content too.In creasing Fe 3O 4 content from 0 to 28.2% considerably increased both the saturated magnetizatio n (Ms) and the coercive force (Hc) from 0 to 23.42 emu/g and 0 to 45.2 Oe,respe ct ively.Since PPY powder is not magnetic,the ferromagnetic properties of the comp osites are attributed to the magnetic Fe 3O 4 nanoparticles.The magnetic F e-3O-4 nanoparticles can improve the thermal stability of Fe 3O 4-polypyrro le nanocomposites due to interaction between Fe 3O 4 particles and PPY chains.