Robust Single-Walled Carbon Nanotube-Coated Aramid Fibers with Tunable Conductivities for Broadband Radar Absorption in Honeycomb Structures

Single-walled carbon nanotubes (SWNTs), renowned for their high strength and electromagnetic properties, provide a potential solution for next-generation honeycomb-structured radar-absorbing materials (HRAMs). However, the integration of SWNTs into HRAMs is hindered by challenges including poor dispersion, wash-off loss, and the absence of scalable, compatible fabrication methods. Herein, we address these challenges by synthesizing tunable conductive SWNT-coated aramid fibers (SWNT-AF) via a continuous dip-coating method and integrating them into aramid paper-based composites (APBC) to fabricate HRAMs. The SWNT-AF serve as both structural reinforcements and dielectric loss centers within APBC, avoiding direct dispersion of SWNTs into the pulp and thereby mitigating agglomeration and wash-off loss. The optimized APBC, reinforced with these tailored fibers, exhibit improved dielectric properties, resulting in enhanced microwave absorption performance. The fabricated HRAMs achieve an effective absorption bandwidth of 14.8 GHz (2.0-18.0 GHz) with an ultralow SWNT loading of 0.2 wt % and a thin thickness of only 30 mm, demonstrating a reflection loss of -47.78 dB. These results highlight the potential of SWNT-AF as lightweight, broadband radar-absorbing materials for stealth applications.