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Electromagnetic (EM) wave absorbing materials with superhydrophobic property and enhanced microwave absorbing ability are very important for the application of stealth technologies, especially in humid conditions. In the present work, the electrospinning technique was employed to fabricate NiAc/PVA nanofibers (NFs) from nickel acetate tetrahydrate (NiAc) and poly(vinyl alcohol) (PVA) solution as precursors, while the PVA component was further pyrolyzed and carbonized to obtain Ni/NiO/C NFs. Microwave absorption performance and EM parameters of the prepared NFs were then investigated from 2.0 to 18.0 GHz. Comparative studies between different samples elucidated not only the possible causes for lose mechanisms, but also impedance matching. According to the experimental results, when NiAc/PVA NFs contained 8% NiAc, the calcinated Ni/NiO/C NFs could achieve an optimum reflection loss of − 33.9 dB at 10.4 GHz under a thickness of 2.5 mm and exhibit an effective frequency bandwidth of 5.7 GHz. Furthermore, the membrane of Ni/NiO/C NFs with the best absorption property exhibited robust hydrophobicity and the contact angle was 144.9°, It shows that the obtained Ni/NiO/C NFs have a broad application prospect in waterproof stealth materials. [ABSTRACT FROM AUTHOR]

Microwave absorbing materials with enhanced microwave absorption performance and self-cleaning function are of great interest for military applications and human health caused by electromagnetic radiation pollution. Herein we report the synthesis of FeNi/NiFe 2 O 4 /NiO/C nanofibers (NFs) via electrospinning technique using nickel acetylacetonate (Ni(acac) 2), ferric acetylacetonate (Fe(acac) 3), and N, N -dimethylformamide (DMF)/polyacrylonitrile (PAN) solution as precursor. We also show the abilities of the materials to attenuate electromagnetic microwave and their ease of self-cleaning performance. X-ray diffraction patterns and HRTEM images reveal that the materials possess FeNi, NiFe 2 O 4 , NiO and graphite. HAADF-STEM images show that the magnetic nanoparticles distribute uniformly along the fibers. Contrast experiments had been conducted on different calcination temperatures to elucidate the impedance matching and loss mechanism. Based on the results of the experiment, excellent microwave absorption was exhibited by blending the NiFe 2 O 4 /NiO/CNFs and FeNi/NiFe 2 O 4 /NiO/CNFs into paraffin at 50 wt% and 5 wt%, respectively. Moreover, the contact angles (CA) of the as-prepared fiber films calcined at 650, 750 and 950 °C were 143°, 141° and 144°, respectively, indicating that fiber films exhibited excellent hydrophobicity and self-cleaning function. It suggested that the as-obtained NFs had an excellent application prospect in self-cleaning microwave absorbing materials. [ABSTRACT FROM AUTHOR]