MXene-Coated Liquid Metal Elastomers: Permeable, Stretchable, 3D-Printable Electromagnetic Interference Shielding Materials for Electronic Skins

Permeable, stretchable, and 3D-printable electromagnetic interference (EMI) shielding materials are essential for next-generation electronic skins, yet current materials rarely combine all these attributes. Here, we present a strategy to fabricate multifunctional materials via the phase separation induced porosity (PSIP). In this design, thermoplastic polyurethane (TPU) serves as the stretchable matrix. Gallium-indium-tin liquid metal (LM) microdroplets act as conductive fillers, and MXene nanosheets stabilize the LM interface. The resulting MXene@LM/TPU elastomers exhibit excellent permeability, high stretchability (∼471%), outstanding EMI shielding effectiveness (87.0 dB), and 3D printability for the fabrication of shape-adaptive architectures. Notably, the enhanced permeability does not induce LM leakage or compromise mechanical robustness─challenges in LM-based composites. The percolated network remains stable after 200% cyclic tensile strains, with <1% SE degradation after 500 bending cycles. This work offers a strategy for engineering high-performance EMI shielding materials, promising applications in wearable electronics, soft robotics, and human-interactive devices.