LAUSR

Abstract Lightweight magnetic polyvinylidene fluoride/ferric oxide/polyaniline nanofiber (PVDF/γ-Fe2O3/PANI) foams with excellent microwave absorption performance in the K (18–26.5 GHz) and Ka (26.5–40 GHz) bands were successfully fabricated using heat shaping and a sacrificial templating method. By varying the diameter of the PANI nanofibers (50, 100 or 500 nm), the electromagnetic microwave absorption (EMWA) properties of the composite foams could be precisely tuned. PVDF/γ-Fe2O3/PANI-50 foams with a PANI nanofiber diameter ~50 nm delivered the best all-round EMWA performance, demonstrated by minimum reflection loss (RLmin) values of -38.7 dB at 26.33 GHz and -38.4 dB at 28.9 GHz at an absorber thickness of 2.5 mm. Further, the effective absorption bandwidth (EAB) of the composite could be adjusted to cover the entire 18-40 GHz frequency region simply by changing the absorber thickness (from 1.5-3.5 mm). This work introduces a simple low cost strategy for designing high performance microwave absorbers.