Design of efficient microwave absorbers based on multi-layered polyaniline nanofibers and polyaniline nanofibers/Li0.35Zn0.3Fe2.35O4 nanocomposite

•Polyaniline nanofibers/Li0.35Zn0.3Fe2.35O4 (PANI/LZFO) nanocomposite was synthesized by interfacial polymerization method.•Microwave absorption mechanism for PANI nanofibers/LZFO nanocomposite is proposed.•Single- and double-layer microwave absorbers were designed based on PANI nanofibers and the nanocomposite.•The minimum RL value of the double-layer absorber can reach −57.5 dB with a total thickness of 2.0 mm, and the bandwidth with RL below −10 dB reaches 5.5 GHz.

Polyaniline (PANI) nanofibers/Li0.35Zn0.3Fe2.35O4 (LZFO) nanocomposite was synthesized through interfacial polymerization with D-camphorsulfonic (D-CSA) as a dopant. The structure and morphological characteristics of the samples were examined through Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy. The microwave absorption properties of single- and double-layer microwave absorbers were investigated in the frequency range of 2-18 GHz. For the single-layer absorbers, the absorption property of PANI nanofibers/LZFO nanocomposite is more efficient than that of PANI nanofibers and LZFO because of enhanced interfacial effects and impedance matching. The reflection loss (RL) of PANI nanofibers/LZFO nanocomposite can reach −37 dB at 14.6 GHz with 2.0 mm thickness, and the corresponding bandwidth (RL < −10 dB) can reach 4.8 GHz. The microwave absorption properties of the double-layer absorbers are more excellent than those of the single-layer absorbers. For the double-layer absorbers, the minimum RL can reach −57.5 dB when the absorption layer is filled with 0.6 mm thick PANI nanofibers/LZFO nanocomposite and the matching layer is filled with 1.4 mm thick PANI nanofibers, and the bandwidth with RL below −10 dB reaches 5.5 GHz. Therefore, PANI nanofibers/LZFO nanocomposite can be used as potential candidate for microwave absorbers with thin thickness and strong absorption.