Micro-porous Ag/MXene/polymer thin coatings constructed by water droplet templating for highly efficient electromagnetic interference shielding

Ultrathin and lightweight electromagnetic interference (EMI) shielding materials tailored for microminiaturized electronic devices have become an urgent necessity. Porous polymeric composites incorporated with conductive fillers could be a promising candidate to meet such challenge. In the current study, pore-formation technique based on the inverse emulsion - breath figure process was utilized to shape highly porous polymeric coating with multi-layered arrays of micro-pores, uniformly embedded with Ti 3 C 2 T x MXene. By tuning the influential parameters, including MXene content, coating thickness, and pore sizes, an EMI shielding effectiveness value of 38 dB could be obtained from the composite coating. The 3D conductive pathways shaped by the Ti 3 C 2 T x flakes and the existence of the multiple interfaces within the multi-layered porous matrix of the polymer-MXene coatings (PMCs) were assumed to establish the fine EMI shielding performance. The PMC was further coated onto the circuit board and proven to function well as an ultra-thin EMI shielding layer attached to the microminiaturized electronic devices. In-situ metallic reduction induced by the MXene with inherent reducibility was utilized to further enrich the porous matrix of PMCs with Ag nanoparticles, generating Ag-decorated PMCs (Ag-PMCs). The fabricated Ag-PMC with thickness of only 240 μm demonstrated superior EMI shielding performance of an EMI SE value of 70.32 dB and a SSE/t value of 8775 dB cm 2  g −1 . This work sheds light on designing the ultrathin porous coating as EMI shielding materials for cutting-edge electronic devices.