Flexible Sandwich-Structured Silicone Rubber/MXene/Fe3O4 Composites for Tunable Electromagnetic Interference Shielding

There is a pressing demand for efficient electromagnetic interference (EMI) shielding materials with strong electromagnetic wave absorption and low reflection for the protection of next-generation communication technologies and wearable electronic devices. In this work, silicone rubber/MXene/Fe3O4 (SRMF) composites with a sandwich-like structure were fabricated using vacuum-assisted dipping and curing. The top and bottom layers of the SRMF composites are magnetic layers containing Fe3O4 particles and silicone rubber (SR), while the middle layer is a 3D conductive network of MXene aerogel film and SR. This sandwich-like structure enables the composites to effectively shield incident electromagnetic waves and improve the absorption of electromagnetic waves through a mechanism of "absorption–reflection–reabsorption". The electromagnetic shielding performance of a sandwich-structured SR composite containing 1.2 wt % MXene and 20 wt % Fe3O4 reached 55.5 dB, which was higher than that of a blended SRM1.2F20b composite containing the same proportion of MXene and Fe3O4 (23.1 dB), while the power coefficient of reflectivity was 0.65. The SRMF composites also retained their EMI shielding performance after 1000 bending cycles and displayed good tensile strength. These flexible SRMF composites have broad application prospects in the field of electromagnetic protection of wearable devices.