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Abstract

The rapid growth of wireless communication technologies and high-frequency electronics has intensified concerns about electromagnetic interference (EMI), which can compromise device performance and pose risks to human health. Conventional metal-based EMI shielding materials rely heavily on reflection-dominant mechanisms, which can generate secondary electromagnetic pollution and present challenges in terms of weight, corrosion, and environmental sustainability. This thesis addresses these limitations by developing sustainable, absorption-dominant EMI shielding systems through structural design. A bio-based approach was employed using lignin and polyethylene oxide (PEO) blends, which were electrospun into nanofibrous mats to promote multiple internal reflections and wave attenuation. First, the appropriate blend composition was identified through detailed morphological and rheological studies to ensure optimal fiber formation and processability. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coatings were then applied via electrospraying on electrospun layers, introducing conductivity to the layer. Magnetic Fe3O4 nanoparticles were also incorporated to add magnetic loss mechanisms, further increasing absorption. Single- and multilayer configurations, with and without conductivity gradients and magnetic fillers, were systematically designed, fabricated, and characterized to evaluate the EMI shielding effectiveness within the X-band (8.2–12.4 GHz). The results demonstrate that the strategic combination of bio-based nanofibrous architectures, gradient conductivity, and magnetic inclusions yields lightweight, flexible shields with superior absorption performance, offering a promising pathway toward environmentally friendly, high-performance EMI shielding solutions for next-generation electronics.