Jeonbuk National University (JBNU) Professor Kim Tae-hwan (Department of Quantum System Engineering, College of Engineering) and Professor Kim Seong-gon (Division of Chemical Engineering, College of Engineering) led a collaborative research team that has developed a method for fabricating composites capable of implementing neutron shielding materials in a variety of shapes and geometries for radiation protection.

The team devised a method to produce a boron nitride nanotube–polymer composite that is easily moldable, flexible, and suitable for use as a neutron shielding material. They utilized a hydrophilic agarose polymer that exhibits a sol-gel phase transition when cooling from approximately 100 °C to room temperature, together with boron nitride nanotubes, a next-generation nanomaterial, and succeeded in fabricating neutron shields with various shapes and geometries.

※ Sol-gel Phase Transition: A reaction in which a liquid transforms into a viscoelastic solid form.

Boron nitride nanotubes possess excellent mechanical, thermal, and electrical properties as well as thermal neutron shielding characteristics, making them a next-generation nanomaterial suitable for use in harsh environments such as space or nuclear reactors. However, BNNTs have hydrophobic surfaces that do not readily bind to water molecules and tend to aggregate into bundles due to van der Waals interactions between neutral molecules, which has hindered practical application.

To address this, the team modified the surface of BNNTs to render them hydrophilic via non-covalent functionalization. They then fabricated composites with the hydrophilic polymer agarose using the sol-gel phase transition, greatly expanding the practical applicability of the material as a neutron shielding medium.

※ Non-covalent Functionalization: A method of modifying the surface of nanoparticles through hydrophobic interactions with amphiphilic molecules—such as surfactants or amphiphilic polymers—that contain both hydrophilic and hydrophobic groups.

The research team characterized the internal structure and physical properties of the composites using small-angle X-ray scattering and tensile strength tests, and verified the neutron shielding performance through neutron transmission experiments at the HANARO research reactor located at the Korea Atomic Energy Research Institute in Daejeon.

※ Small-Angle X-Ray Scattering (SAXS): Scattering observed within the diffraction angle range of approximately 0.1–10 degrees using high-brightness X-rays.

The research was led by researcher Jeon Sang-woo (Ph.D. student, Department of Applied Plasma Engineering) and researcher Kim Ji-won (M.S., Division of Chemical Engineering, College of Engineering). The paper was published in the latest issue of Nano Letters (IF: 10.8), an internationally leading journal in nanotechnology published by the American Chemical Society (ACS). It was also selected as a supplementary cover article in recognition of being the first practical application of boron nitride nanotubes.

The research team stated, "Through this study, we developed a simple method to produce neutron shielding materials that are easy to mold and process and exhibit excellent mechanical properties," and added, "We expect this to contribute to the further development of composite materials with improved mechanical, electrical, and thermal properties across various fields."

This research was carried out with support from the National Research Foundation of Korea through the Basic Nuclear Research Support Program, the Core Research Support Center Establishment Program, the Pilot Project for Establishing an Industry–Academia Cooperation Platform, the Mid-Career Researcher Support Program, and RIS Energy New Industry.