Facile Synthesis and Microwave-Absorption Properties of Organic-Inorganic CoFe₂O₄/Polyaniline Nanocomposites with Embedded Structure.

Organic-inorganic CoFe₂O₄/polyaniline (CoFe₂O₄/PA) nanocomposites with embedded structures were synthesized by combining the sol-gel auto-combustion process and in-situ oxidative polymerization. The phases and morphologies of the prepared samples were identified. The pure CoFe₂O₄ samples exhibited inferior microwave-absorption properties in a frequency range of 2-18 GHz. Upon the incorporation of PA, the formed CoFe₂O₄/PA nanocomposites exhibited rather good absorption performances. When the sample thickness was 2.5 mm, the maximum reflection loss (RL) reached -22.3 dB, while the RL below -10 dB corresponded to the range of 11.0-17.1 GHz, which contains almost the entire Ku-band, making the structure promising for commercial and military applications. A physical model was employed to explain the effects of the embedded structure on the microwave-absorption performances. The excellent microwave-absorption performances could be attributed to the interfacial polarization and repeated reflection of the microwaves inside the CoFe₂O₄/PA composite.