Compressible polypyrrole aerogel as a lightweight and wideband electromagnetic microwave absorber

Abstract

Three-dimensional aerogel has been expected to be a promising candidate for lightweight absorber. Here, polypyrrole (PPy) aerogels with elasticity characteristic have been obtained via facile oxidative polymerization and freeze-drying techniques. The low density (54 − 61 mg/cm3) and mechanical strength (15.4 − 18.7 kPa at 50% strain) of the PPy aerogels can be achieved by adjusting the FeCl3/Py molar ratios from 1:1.5 to 1.5:1. And as a microwave absorber for the PPy aerogel (FeCl3/Py = 1:1.5, 10 wt% mixed with paraffin), at the thickness of 2 mm, the minimum reflection loss (RL) could reach − 55 dB at 14 GHz and the efficient bandwidth (RL ≤ − 10 dB, 90% absorption) is 5.5 GHz. Increasing the FeCl3/Py molar ratio to 1:1, the efficient bandwidth of the prepared PPy aerogel expands to 5.6 GHz. The high-performance microwave absorption properties and well mechanical capacities of the PPy aerogels highlight their potential application in the microwave absorbing systems.