Frequency-selective/impedance gradient MXene/PPy nanocomposite polyester felt with a broadband electromagnetic wave absorption

A collaborative design of a macro impedance continuous gradient structure and a micro-nanocomposite absorber was developed in this study. Furthermore, frequency-selective fabrics (FSF) with resonance function was laminated to operate over a wide frequency range, preventing weak absorption at low frequencies. First, freezing-interface polymerization using pyrrole was performed in the thickness direction of the MXene-coated polyester felt, forming a concentration gradient of polypyrrole. Then, the obtained MXene/polypyrrole integrated impedance gradient absorbing fabric (MP-IIGF) was used as the substrate, FSF was laminated to build a frequency selective/impedance gradient layer composite structure (FSF/MP-IIGF). F5/MP-IIGF had a total absorption bandwidth of 13.0 GHz, which is 2.4 GHz wider than that of MP-IIGF. The results showed that the frequency selective/impedance gradient structure had a clear frequency spreading control effect and improved the EM wave absorption performance at low frequencies. Thus, these materials are promising candidates to be integrated in EM wave-absorbing protection systems.