This study investigates the influence of silane-treated loofah vine stem microfiber and hybrid magneto-electric fillers (Fe 2 SO 4 and biocarbon) on the electrical, magnetic, and electromagnetic interference (EMI) shielding properties of flexible PVA-based composites. The electrical conductivity increased significantly with hybrid filler loading, and among all specimens, PLF2 exhibited the most balanced and efficient conductive response, reaching 6.5 × 10 −9 S/m, which is 6.5 × 10 6 % higher than neat PVA. This enhanced conductivity is attributed to the formation of semi-continuous conductive networks created by 1.5 vol.% Fe 2 SO 4 and 1.5 vol.% biocarbon, supported by silane treatment that ensures uniform dispersion and low interfacial resistance. Magnetic measurements revealed progressive increases in both real (µ′) and imaginary (µ″) permeability with higher Fe 2 SO 4 content, where PLF3 recorded the highest values—µ′: 3.24–4.20 and µ″: 0.64–1.49—due to the formation of dense magnetically responsive micro-domains that promote domain wall relaxation, dipole rotation, and interfacial polarization. EMI shielding performance followed a similar trend, with PLF3 achieving the maximum SE, ranging from 8.89 dB (E-band) to 30.06 dB (J-band), owing to the synergistic combination of conduction loss from biocarbon, magnetic loss from Fe 2 SO 4 , and multiple reflection pathways created by the fiber network. Overall, the hybrid reinforcement system demonstrates strong potential for flexible EMI shielding applications, with PLF2 being optimal for conductivity-driven designs and PLF3 excelling in magnetic and EMI attenuation mechanisms. This composite show potential for flexible EMI shielding, wearable electronics, sensors and energy storage applications.
Reddy et al. (2026) studied this question.