Gd3+ ionic nano-aggregate clusters enable metallopolymers redox electrolytes as high-performance flexible radiation shielding

In this work, Gd 3+ ionic nano-aggregate clusters were introduced into metallo-polyelectrolytes to balance the conflicts between high mechanical robustness and X-ray attenuation of flexible shielding materials. The segmented polyurethanes (PUs) containing main-chain bisferrocene and pendant sulfonates in hard segments is applied as a macromolecular template for the subsequent self-assembly with Gd 3+ . Rare earths aggregate into dynamic clusters about 2.2 nm, which is beneficial to improve the radiation attenuation ability and mechanical properties of materials. The hierarchical noncovalent interactions (ionic interactions, coordination interactions, hydrogen bonds , and ferrocene-metal interactions, etc.) in the aggregate PUs enable the co-existence of high mechanical strength , large stretchability, and fast radiation dissipation. As a result, this Gd 3+ hybrid bisferrocene-based PU demonstrates extremely high tensile properties (breaking stress = 27.8 ± 0.2 MPa, breaking strain = 576 ± 7%) as well as super atomic shielding efficiency (14.39 cm 2  g −1 ) at 65 keV.