Pukyong National University Develops Lead-Free X-ray Shielding Aerogel, Paving the Way for Safer Medical and Industrial Applications

3D Photon Cage Achieves Up to 97% X-ray Absorption Efficiency
Published in Leading Chemistry Journal Advanced Functional Materials

The research team led by Professor Kim Junghwan (Department of Advanced Materials System Engineering) at Pukyong National University has developed a next-generation X-ray shielding aerogel material that is flexible, super-elastic, and hydrophobic. This breakthrough paves the way for practical applications across various fields, including medicine, military, and industry.

X-ray technology is utilized in a wide range of sectors such as medicine, science, industry, and the military; however, exposure to X-rays poses potential health risks to humans.

According to the research team, the most widely used shielding material at present is lead (Pb), which has several limitations, including toxicity, environmental hazards, and low flexibility. Lead also exhibits poor X-ray absorption efficiency in the 40-88 keV range and is unable to sufficiently block secondary radiation generated when X-rays interact with the material.

Next-generation X-ray shielding aerogel material structure.

Although various studies have been conducted to overcome these issues, previous research has mainly focused on developing two-dimensional (2D) flexible thin-film lead alternatives, which are fundamentally limited in improving X-ray absorption performance due to the restricted attenuation cross-section.

Professor Kim Junghwan's team focused on the fact that three-dimensional (3D) porous aerogels possess low density and high flexibility, and that the repeated absorption, scattering, and reabsorption of photons within the complex pore structure increases photon residence time, thereby significantly enhancing absorption efficiency.

The research team successfully developed a flexible aerogel with a 3D "photon cage" structure by applying a gadolinium (Gd)-based phase-separation-induced strategy. They further enhanced the material by adding a polydimethylsiloxane (PDMS) coating and incorporating the perovskite compound Cs3Bi2I9, resulting in a next-generation X-ray shielding material with super-elasticity, hydrophobicity, thermal insulation, freeze resistance, and quadruple complementary X-ray absorption properties.

The aerogel developed by the team demonstrated outstanding shielding performance across a wide energy range, thanks to the synergistic effect of quadruple complementary absorption and the photon cage structure. Experimental results showed a high X-ray absorption efficiency of 76-97% within the 40-120 kV tube voltage energy range.

To verify the aerogel's applicability in real-world medical environments, the research team collaborated with Samsung Medical Center to successfully test its shielding performance using CT equipment.

Professor Kim Junghwan stated, "This achievement presents a new structural design paradigm for developing high-efficiency X-ray shielding materials based on light weight and flexibility, and holds significant potential for applications in fields such as medicine, the military, and industry."

This research was supported by the Ministry of Science and ICT, the Ministry of Education, the National Research Foundation of Korea, and the global joint research program at Pukyong National University. The results were published in the world-renowned chemistry journal 'Advanced Functional Materials' (IF=19) under the title 'Photon-Cage-Structured Aerogels with Quadruple Complementary Compounds for Efficient X-ray Absorption.'

PhD candidate Li Shisen (left) and Professor Kim Junghwan.

This content was produced with the assistance of AI translation services.