High-Precision Printing of Flexible MXene Patterns for Dynamically Tunable Electromagnetic Interference Shielding Performance

Abstract

Smart electromagnetic interference (EMI) shielding materials are of great significance in coping with the dynamic performance demands of cutting-edge electronic devices. However, smart EMI shielding materials are still in their infancy and face a variety of challenges (e.g., large thickness, limited tunable range, poor reversibility, and unclear mechanisms). Here, we report a method for controllable shielding electromagnetic (EM) waves through subwavelength structure changes regulated by the customized structure via a direct printing route. The highly conductive MXene ink is regulated with metal ions (Al3+ ions), giving superb metallic conductivity (∼5000 S cm–1) for the printed lines without an annealing treatment. The reversible tunability of EMI shielding effectiveness (SE) ranging from 8.2 dB (“off” state) to 34 dB (“on” state) is realized through the controllable modulation of subwavelength structure driven by stress. This work provides a feasible strategy to develop intelligent shielding materials and EM devices.

Electromagnetic Interference Shielding and Joule Heating Properties of Flexible, Lightweight, and Hydrophobic MXene/Nickel-Coated Polyester Fabrics Manufactured by Dip-Dry Coating and Electroless Plating

“…MXenes are characterized by the general formula M n +1 X n T x , where M represents a transition metal such as titanium (Ti), niobium (Nb), or molybdenum (Mo), X can be carbon or nitrogen, and T denotes surface functional groups (–OH, –O, -Cl or –F) . The hydrophilic surface functional groups enable MXenes to interact effectively with polar polymers without compromising electrical conductivity and facilitate their dispersion in polar solvents, making them suitable for various solution-based processing methods like dip-coating, spraying, and vacuum filtration. − MXenes possess all the essential properties required for efficient EMI shielding materials, including good electrical conductivity, strong absorption, large specific surface area, lightweight, and ease of processing. ,− Furthermore, MXenes have garnered significant attention in diverse fields, spanning energy, electronics, catalysis, optics, sensors, environmental science, and electromagnetism. − Nevertheless, despite these advantages, MXenes are prone to oxidation when exposed to moisture in ambient conditions, resulting in a deterioration of their exceptional electrical properties over time . Oxidation typically occurs at sites where hydroxyl (–OH) groups are located, causing electrons on titanium (Ti) atoms to be drawn toward oxygen (O) atoms within the hydroxyl groups.…”