Polypyrrole/Modified PDMS/MXene Sandwich-Structured Materials With Electromagnetic Shielding Properties

This study reports a sandwich-structured composite with polypyrrole (PPy)/modified polydimethylsiloxane (PDMS) outer layers and MXene/polyvinyl alcohol (PVA) intermediate layer. The PDMS matrix contains carboxylated carbon nanotubes with Fe 3 O 4 (MWCNT@Fe 3 O 4 ), liquid metal-copper alloy (LM@Cu), carbon fibers, and expanded microspheres. PPy polymerized on PDMS enhances conductivity, while MXene/PVA acts as a reflective layer. Structural, morphological analyses, and simulation confirm the uniform dispersion of fillers, successful Fe 3 O 4 and Cu modifications, and interfacial bonding within the sandwich architecture. The composite shows 2.21 Ω cm resistivity through conductive filler interactions. EMI shielding in X-band reveals 80.57 dB total shielding effectiveness, exceeding individual components (PPy/PDMS: 43.54 dB; MXene/PVA: 5.62 dB). This results from multi-phase shielding: porous PPy/PDMS enables impedance matching and wave absorption, while MXene creates internal reflection cycles. The design achieves 93% wave absorption through gradient conductivity and magnetic-electric synergy, offering a scalable approach for flexible, lightweight shielding materials. Highlights Sandwich composite achieves high EMI shielding of 80.57 dB in X-band. PDMS matrix enhanced by MWCNT@Fe 3 O 4 , LM@Cu, and expanded microspheres. In situ polymerized PPy and MXene/PVA layer enables multi-stage shielding. Innovative design yields 93% EMI absorption and low resistivity of 2.21 Ω cm. Provides a flexible, scalable EMI shielding solution for advanced electronics.