Effects of the Fe_3O_4 Content on the Electromagnetic Parameters of Magnetic and Conductive Polyaniline Nanoparticles

Electric conductive and magnetic permeable nanocomposites with electromagnetic wave absorbing property were synthesized by emulsion polymerization with dodecyl benzene sulfonic acid(DBSA)as the emulsifier and dopant and ammonium persulfate(APS)as the oxidant.The microstructures of the synthesized nanocomposites were characterized by means of TEM,SEM,FT-IR and XRD.The results indicate that the synthesized Fe3O4/PANI/DBSA nanocomposites possess the core-shell structure with magnetic oxide(Fe3O4)as core and conducting polyaniline(PANI)doped by DBSA as shell,the average diameter of the Fe3O4-/PANI/DBSA nanocomposites is about 100 nm.The effects of relative content of Fe3O4 and aniline on the permittivity(e',e″)and permeability(μ',μ″)of the nanocomposites were studied by the 3 cm waveguide measurement line method.The results show that the magnetic and dielectric losses of the nanocomposites are improved by Fe3O4,and the imaginary part of permeability(μ″)increases with increasing the Fe3O4 content,while the imaginary part of permittivity(e″)decreases at first and then increases with the increase of the Fe3O4 content.The nanocomposites with Fe3O4 content of 40% have the maximum μ″ of 0.85 at 4 GHz and maximum e″ of 9.62 at 2GHz.