Liquid Metal Grid Patterned Thin Film Devices Toward Absorption‑Dominant and Strain‑Tunable Electromagnetic Interference Shielding

The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.

Bio‑imitative Synergistic Color‑Changing and Shape‑Morphing Elastic Fibers with a Liquid Metal Core

The systematic integration of color-changing and shape-morphing abilities into entirely soft devices is a compelling strategy for creating adaptive camouflage,electronic skin,and wearable healthcare devices.In this study,we developed soft actuators capable of color change and programmable shape morphing using elastic fibers with a liquid metal core.Once the hollow elastic fiber with the thermochromic pigment was fabricated,liquid metal(gallium)was injected into the core of the fiber.Gallium has a relatively low melting point(29.8℃);thus,fluidity and metallic conductivity are preserved while strained.The fiber can change color by Joule heating upon applying a current through the liquid metal core and can also be actuated by the Lorentz force caused by the interaction between the external magnetic field and the magnetic field generated around the liquid metal core when a current is applied.Based on this underlying principle,we demonstrated unique geometrical actuations,including flower-like blooming,winging butterflies,and the locomotion of coil-shaped fibers.The color-changing and shape-morphing elastic fiber actuators presented in this study can be utilized in artificial skin,soft robotics,and actuators.