Enhanced microwave absorption in organogels: The synergy of polar molecules and magnetic particles

Abstract

Herein, wideband microwave absorbing materials with high flexibility are developed by creating a novel layered organogel composite consisting of carbonyl iron particles (CIP) and polyacrylamide (PAM), employing ethylene glycol (EG) as the solvent. The microwave absorbing properties of layered absorbers with different CIP contents are investigated over the 1–18 GHz range. An integrated stratified architecture was obtained using polar EG molecules and magnetic CIP particles, which were the main contributors to magnetic and dielectric losses in the PAM matrix. The results indicated that the minimum reflection loss reaches a value of −48.0 dB at a thickness of 2 mm and a frequency of 15.5 GHz; meanwhile, an effective absorption bandwidth of 3.2 GHz in the C-band can also be obtained. An analysis of the absorption mechanism shows that the combination of an impedance-matching layer composed of CIP magnetic particles and an absorption layer composed of EG polar molecules in the PAM matrix provides strong broadband absorption in the C-band. Overall, the CIP/EG@PAM organogel composites have simple preparation, high flexibility, and it has adhesion. This study provides a new strategy for designing wideband microwave absorbing materials.