Dielectric Modulation in Core–Shell Halloysite-Nanotubes@Conductive-Polymers for Broadband Electromagnetic Wave Absorption

Dielectric modulation is a vital approach for developing efficient electromagnetic wave absorption (EMA) materials. However, it is still an attractive challenge to enhance the dielectric properties of composites by adjusting the conductivity. Here, this paper reports a series of core–shell halloysite-nanotubes@conductive-polymers (HNTs@CPs) synthesized by constructing a conductive network on the surface via a modification approach, where CPs include polythiophene (PTh), polyaniline (PANI), and polypyrrole (PPy). The modified composites have outstanding electrical conductivity and dielectric loss capabilities, resulting in an excellent EMA performance. Among them, the HNTs@PPy has an effective absorption bandwidth (EAB) of up to 6.3 GHz covering C, X, and Ku bands with a minimum reflection loss (RLmin) of −48 dB. This work presents a technological strategy for achieving dielectric modulation to develop efficient EMA materials.