Deep eutectic solvent mixed ionic liquids achieve highly enhanced electromagnetic wave absorption and mechanical properties

Abstract

The pursuit of an electromagnetic wave (EMW) absorption gel material that demonstrates an optimal loss range for efficient dissipation of EMW, complemented by outstanding mechanical properties to mitigate external loads, is highly desirable. However, the issue of conflict between optimal conductivity and mechanical performance in EMW absorption gel materials has yet to be adequately resolved. Herein, we encapsulate ionic liquids (ILs) through deep eutectic solvents (DESs) via one-step UV polymerization to tackle this challenge. The presence of LiTFSI in the ILs, owing to its ion-rich characteristics, offers a feasible approach for modulating the conductive loss capability, and chloride choline (ChCl) in the DESs can serve as a hydrogen bond acceptor forming hydrogen bonds to significantly enhance the mechanical properties of the gel. The prepared gels not only exhibit exceptional formability, high adhesion (5.25 × 10⁵ Pa s), and stretchability (1420%) but also demonstrate superior EMW absorption performance with an RL_min value of −63.00 dB at 1.90 mm and an effective absorption bandwidth (EAB) of 4.00 GHz and 5.60 GHz in X and Ku bands, respectively. Overall, our strategy successfully integrates the gel materials' EMW absorption characteristics with their mechanical properties and may provide promising applications in EMW protection devices.