Dual-shelled CoFe@C@PPy hybrid fibers toward efficient microwave absorption, wide-angle RCS suppression and hydrophobic performance

Dual-shelled CoFe@C@PPy fibers are fabricated via microwave hydrothermal and in situ pyrrole polymerization. • PPy loading tunes magnetic-dielectric balance to optimize impedance matching. • Max RCS reduction hits 37.6 dB m² at 35°, RCS <−10 dB·m² for |θ|≥ 4°. • 134.2° contact angle brings excellent hydrophobicity and moisture resistance. The development of microwave absorbing materials (MAMs) with both wide-angle radar stealth capability and moisture resistance has become an urgent requirement for practical deployment. In this work, CoFe@C precursors are rapidly prepared via a microwave-assisted hydrothermal method, followed by in situ polymerization of pyrrole (Py) to construct dual-shelled CoFe@C@PPy hybrid fibers with different PPy loadings. The dual-shell architecture enables systematic regulation of the magnetic-dielectric balance and impedance matching. At an ultrathin thickness of 2.1 mm, the optimal sample achieves a minimum reflection loss (RL) of −52.06 dB at 13.14 GHz and a maximum effective absorption bandwidth (EAB) of 5.92 GHz. More importantly, wide-angle (0–90°) radar cross-section (RCS) simulations reveal outstanding suppression capability, with a maximum RCS reduction of 37.6 dB m 2 at an incident angle of 35°, demonstrating stable performance under oblique illumination in real radar detection scenarios. In addition, the optimal sample exhibits a water contact angle of 134.2°, showing good anti-humidity performance. This work provides a strategy for the design of dual-shelled microwave absorbers with excellent wide-angle radar cross-section reduction through interfacial polarization engineering. Download: Download high-res image (473KB) Download: Download full-size image