Lightweight, flexible, and antimicrobial X-ray shielding composites with liquid metal-derived bismuth-tin core-shell particles

Abstract

The extensive use of low-energy X-rays in clinical diagnostics increased radiation exposure, growing concerns for the health of patients and healthcare professionals. Lead has long served as a traditional material for radiation shielding owing to its high density and atomic number; however, concerns have arisen due to its toxicity and substantial weight. In this study, we developed flexible and wearable radiation protection materials by employing a layered structure comprising liquid metal-derived bismuth-tin (BiSn) core-shell particles embedded in a thermoplastic polyurethane (TPU) matrix. The structural and mechanical properties of the TPU-BiSn composites were thoroughly investigated. The use of liquid metal particles (LMPs) resulted in outstanding flexibility (retained the flexibility of TPU matrix), while their oxide shell strengthened the composites significantly (∼15 % enhancement in the tensile strength at break point). The TPU-BiSn composites exhibited promising X-ray attenuation properties. X-ray attenuation efficiency surpassed 99 % for 5 mm thick composite sheets, suitable for mammographic diagnostics in the energy range of 20–30 kVp. Increasing particle loading improved shielding efficiency for higher energy ranges (40–90 kVp), with predictions extending to 90–120 kVp, demonstrating their suitability for composites that comply with ASTM standards for radiation attenuation gloves. In addition, the composite sheets displayed contact-active antimicrobial properties, rendering them appealing for various healthcare applications. Given the availability of materials and the feasibility of production, these composites hold significant potential for practical implementation in real-world applications.