Optimal particle distribution induced interfacial polarization in bouquet-like hierarchical composites for electromagnetic wave absorption

Dielectric loss is greatly important for electromagnetic wave absorption. However, the detailed mech-anism for this interfacial polarization is still sorely lacking and the main contribution of dielectric loss in the supported materials has never been investigated until now. Here, we have designed a model dielectric material with a carbon-based supported structure in order to explain the main contribution of dielectric loss originated from its interfacial polarization. The experimental and theoretic results proved that the complicated nanoparticles (NPs) supported on carbon substrate (MOF-74-S1) with optimal particle distribution can form three kinds of interfacial polarizations compared with MOF-74-S2, which mainly contributes to the dielectric loss of the carbon-based composites. The optimal composition and distribution of the NPs bring enhanced dielectric loss and the best electromagnetic wave absorbing properties, with a minimum reflection loss of-33.5 dB and a broad effective absorption bandwidth of 7.6 GHz at a thickness of 2.3 mm. These findings indicate that the optimal distribution of nanoparticles is one of the promising methods to enhance the dielectric loss. (c) 2021 Elsevier Ltd. All rights reserved.