Polypyrrole/Modified <scp>PDMS</scp> / <scp>MXene</scp> Sandwich‐Structured Materials With Electromagnetic Shielding Properties

ABSTRACT 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.