Flexible and lightweight radiation shielding sponges consisting of sulfated tungsten oxide and bismuth halide composites

Lead’s high density (density of ∼ 11.34 g/cm) facilitates X-ray attenuation, but its mass and toxicity limit applicability. Therefore, it is essential to replace Pb with lighter and nontoxic shielding materials; however, alternative shielding usually exhibits inferior performance to Pb. In this study, we successfully developed efficient radiation shielding sponges with a light weight (density of ∼ 1 g/cm) and a coin shape (thickness of 3 mm and diameter of 25 mm) by combining polymeric Polydimethylsiloxane (PDMS), sulfated tungsten oxide (S-WO), and bismuth halides. The synthesized S-WO powder, PDMS/S-WO and PDMS/S-WO/BiI sponges are examined using numerous techniques, such as XRD, FE-SEM with EDX/mapping, HR-TEM with EDX/mapping, XPS, BET, TGA, FT-IR and mechanical properties analysis. The XRD patterns revealed no significant peak shifts, indicating that sulfation had no discernible impact on the crystal structure or phase composition of WO. SEM analysis of PDMS/S-WO, PDMS/S-WO/BiI sponge indicated an even distribution of S-WO and bismuth halide particles within the PDMS matrix. Our novel porous sponge matrices of PDMS and S-WO effectively adsorbed bismuth halide salts on their porous surfaces, forming intimate interfaces and uniform dispersions in the composites. The shielding sponge exhibits high X-ray attenuation. Coin-shaped PDMS/S-WO/BiI demonstrated 90.2 % X-ray shielding efficiency at 60 kV, a top value for non-heavy-metal shields. This study investigates the development and characterization of PDMS/S-WO/BiI composite materials aimed at enhancing X-ray shielding effectiveness. The composite leverages the high atomic number and density of S-WO and BiI to improve X-ray attenuation, while the flexibility and chemical stability of PDMS provide mechanical robustness and ease of fabrication. Through a series of experimental evaluations, we demonstrate that the PDMS/S-WO/BiI composite exhibits superior X-ray shielding capabilities compared to conventional materials. This work demonstrates significant progress in flexible, high-performance X-ray shielding. The approach provides a foundation for developing lightweight, radiation-protective materials using doped metal oxides and halide salts.