Dehydration-Driven Self-Curling for Programmable Multimetallic 3D Architectures

3D metallic architectures are increasingly attractive for wireless communication systems, integrated metallic components, and multifunctional devices. However, reliably constructing geometrically complex, mechanically continuous, and compositionally diverse metallic structures remains challenging, particularly for multimetallic architectures, where differences in elastic modulus frequently led to interfacial delamination or structural failure. A dehydration-driven self-curling strategy that converts direct-written metal-hydrogel precursors into programmable 3D metallic architectures is introduced. By establishing a through-thickness asymmetry in water content, initially planar hydrogel films undergo deterministic shape morphing into intricately curved 3D geometries, achieving bending curvatures up to 0.45 mm^-1, volumetric shrinkage of 56.5%, and post-conversion dimensional fidelities exceeding 90%. Subsequent calcination and atmosphere-controlled reduction yield dense metallic structures. This fabrication route decouples geometric programming from material conversion, enabling high-fidelity shape retention across multiple metal systems. Demonstrations include programmable self-curling Cu/Ni composite tubes that maintain interfacial integrity during high-temperature treatment and operate effectively as radio frequency antennas, exhibiting resonances at 1.575 and 2.4 GHz with return losses below -20 dB. Overall, this work provides a practical fabrication strategy for programmable multimetallic 3D architectures through dehydration-guided morphing and subsequent thermal conversion.