Facile Synthesis of Polyindole/Ni(1–x)Zn(x)Fe(2)O(4) (x = 0, 0.5, 1) Nanocomposites and Their Enhanced Microwave Absorption and Shielding Properties

[Image: see text] The present work reports the fabrication of polyindole (PIN)/Ni(1–x)Zn(x)Fe(2)O(4) (x = 0, 0.5, 1) nanocomposites as efficient electromagnetic wave absorbers by a facile in situ emulsion polymerization method for the first time. The samples were characterized through Fourier transform infrared spectroscopy, UV–vis spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, high-resolution transmission electron microscopy, and vibrating sample magnetometry. The resulting polyindole/Ni(1–x)Zn(x)Fe(2)O(4) (x = 0, 0.5, 1) nanocomposites offer better synergism among the Ni(1–x)Zn(x)Fe(2)O(4) nanoparticles and PIN matrix, which significantly improved impedance matching. The best impedance matching of Ni(1–x)Zn(x)Fe(2)O(4)/polyindole (x = 0, 0.5, 1) nanocomposites was sought out, and the minimum reflection loss of the composites can reach up to −33 dB. The magnetic behavior, complex permittivity, permeability, and microwave absorption properties of polyindole/Ni(1–x)Zn(x)Fe(2)O(4) (x = 0, 0.5, 1) nanocomposites have also been studied. The microwave absorbing characteristics of these composites were investigated in the 8–12 GHz range (X band) and explained based on eddy current, natural and exchange resonance, and dielectric relaxation processes. These results provided a new idea to upgrade the performance of conventional microwave-absorbing materials based on polyindole in the future.