Gradient-Structured PVDF Composite Foams With an Optimized “Capture-Loss-Intercept” Multilayer Design for High Absorption-Dominant Electromagnetic Interference Shielding

The increasing density of wireless electronic devices has intensified electromagnetic interference (EMI), highlighting the limitations of conventional reflection-dominant shielding materials, in which a substantial fraction of incident electromagnetic energy is reflected back into the surrounding environment, potentially causing secondary electromagnetic interference. In this study, we propose a structurally optimized absorption-dominant gradient composite foam based on a “capture-loss-intercept” multilayer design. Multilayer PVDF-based foams were fabricated through a combined vacuum-assisted hot-pressing and supercritical CO 2 (scCO 2 ) foaming strategy, enabling precise control over pore morphology and filler distribution at low filler loadings (2.07 vol%). The resulting hierarchical structure promotes graded impedance matching, multiple internal reflections, dielectric and magnetic losses, and conduction pathways, yielding a synergistic attenuation effect. The optimized trilayer foam achieves an EMI shielding effectiveness of 55.73 dB, a high absorption coefficient (A = 0.9316), and a green shielding index (g s = 13.63), outperforming most previously reported polymer-based foams while maintaining a lightweight configuration. Approximately 99.99% of incident electromagnetic waves are effectively attenuated, demonstrating the structure's superior suppression of secondary reflection. This work provides an efficient and scalable design route for eco-friendly, absorption-dominant EMI shielding materials and offers strong potential for next-generation 5G/6G electronics, aerospace equipment, and lightweight electromagnetic management applications. Highlights A scalable “capture-loss-intercept” multilayer design for absorptive EMI shield. High EMI SE of 55.73 dB is achieved at low 2.07 vol% filler loading. A high green shielding index (gs = 13.63) for near-zero secondary pollution. scCO 2 foaming for lightweight, enhanced EMW dissipation & interface polarization.