Hydrophilic Modification of Gadolinium Oxide by Building Double Molecular Structures

With the rapid growth of nuclear energy, effective shielding of radioactive nuclear by-products is critical for safety and environmental protection. Gadolinium (Gd) is ideal for neutron shielding due to its exceptionally high thermal neutron capture cross-section. Despite significant progress in developing various Gd-based shielding materials, poor interfacial compatibility between Gd₂O₃ and polymer matrices remains a significant limitation. In this study, we addressed this challenge by successfully modifying Gd₂O₃ nanoparticles (Gd₂O₃@SIT-M) through the construction of a dual-layer molecular coating using electrostatic interactions. Initially, Gd₂O₃ was functionalized with the silane coupling agent 3-(trihydroxysilyl) propyl-1-propane-sulfonic acid (SIT), followed by subsequent assembly of polyether amine M2070 onto this modified surface. The combined presence of hydrophilic sulfonic acid groups from SIT and amine-ether groups from M2070 endowed Gd₂O₃@SIT-M nanoparticles with excellent hydrophilicity, significantly reducing their aqueous contact angle to 14.34°. Consequently, this modification strategy notably enhanced the dispersion stability of Gd₂O₃ nanoparticles in aqueous solutions and polymer matrices. The developed approach thus provides an effective pathway for fabricating advanced polymer-based neutron shielding materials with improved dispersibility, stability, and overall performance.