Synergistic Absorption Mechanism in Flexible Polymer Composites Reinforced with Rare Earth Cobaltite and Molybdenum Carbide for EMI Shielding Applications

Abstract The sudden growth of digital devices and fifth-generation (5G) communication systems has generated increasing concerns regarding electromagnetic interference (EMI) shielding in advanced technological applications, due to the high necessity for development of flexible, lightweight and efficient shielding materials. In this study, low thickness polymer composite films based on poly(vinylidene fluoride) polymer that is incorporated with gadolinium cobaltite and molybdenum carbide fillers were successfully fabricated through a solution casting technique. The chemical, structural, and morphological characteristics of the composite films were investigated using XRD, FTIR, FESEM, HR-TEM, tensile strength and contact angle. Thermal stability was assessed through thermogravimetric analysis (TGA), and electromagnetic properties were evaluated in terms of complex permittivity and permeability across the X-band frequency range. The EMI shielding was examined in terms of shielding effectiveness due to absorption, reflection, and transmission and further validated using CST software. The selected composite film with an ultralow thickness of ∼0.15 mm exhibited a maximum EMI shielding efficiency of ∼49 dB in the X-band region with the absorption dominant shielding as the primary attenuation mechanism. The composite films displayed an enhanced mechanical strength and hydrophobicity behavior, making them suitable for flexible and durable shielding applications. These results suggest that the developed PVDF/GdCoO3/Mo2C composite films are promising candidates for advanced electromagnetic interference shielding applications in wearable electronics, stealth technology, and defense systems.