Facile route to controlled iron oxides/poly(3,4-ethylenedioxythiophene) nanocomposites and microwave absorbing properties

Electromagnetic iron oxides/poly(3,4-ethylenedioxythiophene) (PEDOT) nanocomposites were successfully synthesized via a simple one-step method using FeCl3/ ammonium persulfate (APS) as the composite oxidants. The iron oxide nano-materials were formed in the polymer matrix. By simply adjusting the molar ratio of Fe3+ to Fe2+ (represented by [Fe3+]/[Fe2+] ratio), the composites were controlled to be α-FeOOH/PEDOT nanorods or γ-Fe2O3/PEDOT nanoparticles. Transmission electron microscope, X-ray diffraction and Fourier transform infrared used to characterize the morphologies and constitutes of the nanocomposites. The results suggested that both of α-FeOOH and γ-Fe2O3 were nanocrystals, which were coated by PEDOT to form a core-shell structure. The conductivities of the composites were in the range of 10−3 to 10−1  S/cm and the saturation magnetization varied from 5 emu/g to 46 emu/g correspondingly. Moreover, the composite exhibited excellent microwave absorbing property with a minimum reflection loss of about −44 dB when [Fe3+]/[Fe2+] ratio was 3. This study provides a novel method to realize the transformation of iron oxides under mild conditions and synthesize electromagnetic composites with controlled morphology and properties.