Janus Dual Self-Strengthening Structure of Bi 2 O 3 /Gd 2 O 3 Nanofibrous Membranes for Superior X-Ray Shielding.

Bi 2 O 3 /rare earth oxide biphasic absorbers are attractive for high-efficiency X-ray shielding due to the complementary X-ray absorption effects. However, its application is severely hindered by poor interphasic contact. Here, a new Janus interface engineering strategy is reported for the construction of continuous and flexible Bi 2 O 3 /Gd 2 O 3 crystal nanofibrous membranes (FJNMs) with micro/nano dual self-strengthening interphasic adhesion. This strategy facilitates online micro-interlocking between Bi 2 O 3 /Gd 2 O 3 nanofibers and in situ nano-grain fusion between Bi 2 O 3 /Gd 2 O 3 crystals, significantly enhancing the adhesive strength at the Bi 2 O 3 /Gd 2 O 3 interface. Additionally, the synergistic shielding effect from Bi 2 O 3 /Gd 2 O 3 absorption and multiple reflections in Bi 2 O 3 and Gd 2 O 3 crystal lattices make the nanofibrous membranes a superior X-ray radiation barrier. The FJNMs demonstrate integrated features of exceptional X-ray shielding efficiency (91%-100%), robust interfacial adhesion (lap-shear strength >3.8 MPa), prominent flexibility, lightweight, and outstanding breathability. The design concepts of fibrosing biphasic absorber assemblies pave the way for asymmetrically assembling biphasic materials, setting the stage for a fundamental shift in next-generation radiation shielding materials.