Electrospun polymer-based nanocomposite fibers for conformable and lead-free radiation shields

Ionizing radiation is indispensable in medical imaging and radiotherapy, yet it poses a persistent risk for both medical staff and patients. Current protection relies on lead-based sheets that are rigid, heavy, toxic and poorly recyclable, motivating lightweight, flexible and more sustainable alternatives. Electrospinning provides polymer nanofibrous architectures with high surface-area-to-volume ratio, tunable porosity and the integration of functional, radiation-shielding fillers. However, attenuation rules established for dense materials cannot be directly transferred to porous electrospun mats, where fiber diameter, void fraction and filler distribution govern photon interactions and mechanical integrity. Such systems remain largely unexplored within a sustainability-oriented materials engineering framework. Here, we report lead-free composite mats produced by fully water-based electrospinning of poly(vinyl alcohol) (PVA), followed by citric-acid crosslinking and thermal esterification to ensure water stability. High-Z oxide fillers (WO3 and Bi2O3) are incorporated at different loadings and architectures to balance attenuation and wearability. Filler dispersion in the aqueous PVA precursor is evaluated and optimized prior to electrospinning to minimize agglomeration and promote uniform distribution. Electrospinning parameters (solution concentration, flow rate, applied voltage and collecting distance) are tuned to obtain uniform mat deposition. Morphology and filler distribution are assessed by SEM, chemical composition and crosslinking by FTIR, and mechanical response by tensile testing. X-ray shielding is demonstrated through qualitative irradiation tests and supported by attenuation estimates from NIST XCOM-based simulations, showing a clear reduction of transmitted signal with increasing filler content while maintaining flexibility and low density. Overall, these green-processed nanofibrous composites highlight electrospinning as a viable route toward next-generation, lead-free radiation protection for clinical settings, with potential translation to research laboratories and space-radiation environments.