Lignin-based multilayer electrospun mats for absorption-dominant electromagnetic interference shielding

Electromagnetic interference (EMI) has become a growing concern with the proliferation of electronic devices, necessitating sustainable and efficient shielding solutions that surpass conventional reflection-based materials. In this work, we present a bio-derived and novel multilayer nanocomposite EMI shielding system engineered from electrospun lignin/poly(ethylene oxide) (PEO) nanofibers and electrosprayed ethylene glycol-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) coatings with tunable conductivity. The incorporation of Fe 3 O 4 nanoparticles and the introduction of strategic conductivity gradients enabled absorption-dominant shielding by enhancing magnetic and Ohmic losses, impedance matching, and internal scattering mechanisms. A comprehensive rheological study revealed that increasing the PEO content induced a transition from viscous to solid-like behavior, with relaxation times exceeding 50 s, a crucial factor for stable jet formation and uniform fiber morphology. At a lignin-to-PEO ratio of 60/40, the electrospun mats exhibited superior mechanical properties (tensile strength: 4.0 ± 0.8 MPa; tensile modulus: 90.1 ± 8.1 MPa), making them ideal for multilayer fabrication. The final shield, only ∼ 300 µm thick, achieved a remarkable shielding effectiveness of 70 dB and a specific shielding effectiveness (SSE/t) of 5185 dB cm 2 g −1 in the X-band (8.2–12.4 GHz), with an absorbance of 0.66, confirming its absorption-dominant character. This work demonstrates the synergistic use of sustainable materials, nanostructural engineering, and rheological optimization to create lightweight, flexible, and eco-friendly EMI shielding systems. The proposed multilayer design holds significant potential for future applications in aerospace, wearable electronics, and next-generation communication technologies.