Liquid Metal-Ionogel Core–Shell Fibers for Reflection-Suppressed Electromagnetic Interference Shielding and Strain Sensing
Yichao Wang, Jingli Tang, Liqian Huang, Xueli Wang, Jianyong Yu
Abstract
Electromagnetic interference (EMI) shielding fibers are crucial in practical uses for their flexibility and one-dimensional form. However, their application is limited by poor compatibility between EMI shielding components and fiber substrates, and high electromagnetic wave reflectivity. Herein, a core/shell-structured EMI shielding fiber is introduced, featuring a core of Ga-In-Sn-Zn alloy, Carbopol, and air bubbles, and a shell of ionogel formed from copolymerized acrylamide and acrylic acid. A single fiber achieves a total shielding effectiveness of ∼35 dB within the 2-18 GHz range, which increases to ∼70 dB when three fibers are stacked. Remarkably, the fiber demonstrates enhanced EMI shielding performance following stretching and recovery. Additionally, it exhibits excellent impedance matching, with a reflection power coefficient as low as 0.14 at 10 GHz. The fiber's EMI shielding mechanism encompasses reflection shielding, absorption shielding─attributable to conduction loss and polarization loss─and multiple reflection shielding. Furthermore, the fiber shows potential as a strain sensor. This research offers an effective strategy for creating flexible fibers with high EMI shielding capabilities and low EM wave reflection.