Self-Healing Liquid\nMetal Magnetic Composite Films\nfor Wearable Sensors and Electromagnetic Shielding

Film\nmaterials exhibit excellent potential for intelligent\nwearable\ndevices and flexible electronic components owing to their being lightweight,\nthin, and flexible. However, their application faces several challenges\nsuch as their poor mechanical and self-healing properties. Herein,\na composite film comprising poly(vinyl alcohol) (PVA) as the matrix,\na gallium-based liquid metal, and conductive magnetic nickel was fabricated.\nThe film exhibits high conductivity, tensile strength, and self-healing\nability as well as good electromagnetic interference (EMI) shielding\nperformance. The excellent flexibility and overall EMI shielding performance\nof the PVA-based composite film are attributed to the introduction\nof liquid metals, containing abundant hydrogen bonding sites. This\nPVA-based composite film exhibits excellent mechanical characteristics\n(stress 28 MPa, strain 180%) owing to its superb flexibility. The\ncomposite film also has self-healing ability, allowing it to continue\nworking after self-healing. In addition, the PVA-based composite film\nexhibits good EMI shielding performance through multiple loss mechanisms.\nThe film (thickness 0.4 mm) exhibits an overall shielding performance\nof up to 26 dB in the X-band (8.2–12.4 GHz). The average total\nshielding effectiveness of the pure PVA film increased from 0.4 to\n24.7 dB (a 6075% increase) after the introduction of nickel and liquid\nmetals. This multifunctional magnetic composite film has excellent\npotential for intelligent wearable devices, flexible electronic components,\nand strain sensors.