Hierarchical hybrid conductive powders derived from Ag-deposited Janus particle/MWCNT nanocomposites for enhanced microwave absorption

In this study, snowman-like Janus particles (PDVB/PS@SiO 2 ) were proposed as carriers of Ag nanoparticles (Ag@J) to construct a hierarchical hybrid conductive powders by further admixing with MWCNTs for the development of high-performance microwave-absorbing materials. The Ag@J/MWCNT composite powders have several advantages in microwave absorption, such as the polarization of SiO 2 hemispheres, multiple reflections and scattering of electromagnetic waves in the hollow cavity of PDVB/PS hemispheres, improved conductivity and dielectric loss originating from the dense deposition of Ag nanoparticles and incorporation of MWCNTs. Furthermore, the composite powders allow the interfacial polarization and favorable impedance matching. Notably, the asymmetric hemispheres of the Ag@J particles result in close packing, further reducing the transmission of electromagnetic waves. The Ag@J particles demonstrated a minimum reflection loss (RL min ), indicating their potential application in microwave absorption. When further integrated with MWCNTs, the Ag@J/MWCNT composite powders, containing 36.4 wt% of Ag@J, exhibited strong absorption (−27 dB), wide absorption bandwidth (16.5 − 18 GHz), and a low thickness (5.5 mm). The Janus particles reported in this study show high potential applications in microwave-absorbing powder materials.