Ultra-broadband microwave absorber and high-performance pressure sensor based on aramid nanofiber, polypyrrole and nickel porous aerogel

Electronic devices have become ubiquitous in our daily lives, leading to a surge in the use of microwave absorbers and wearable sensor devices across various sectors. A prime example of this trend is the aramid nanofibers/polypyrrole/nickel (APN) aerogels, which serve dual roles as both microwave absorbers and pressure sensors. In this work, we focused on the preparation of aramid nanofibers/polypyrrole (AP15) aerogels, where the mass ratio of aramid nanofibers to pyrrole was 1:5. We employed the oxidative polymerization method for the preparation process. Following this, nickel was thermally evaporated onto the surface of the AP15 aerogels, resulting in the creation of an ultralight (9.35 mg·cm⁻³). This aerogel exhibited a porous structure. The introduction of nickel into the aerogel aimed to enhance magnetic loss and adjust impedance matching, thereby improving electromagnetic wave absorption performance. The minimum reflection loss value achieved was −48.7 dB, and the maximum effective absorption bandwidth spanned 8.42 GHz with a thickness of 2.9 mm. These impressive metrics can be attributed to the three-dimensional network porous structure of the aerogel and perfect impedance matching. Moreover, the use of aramid nanofibers and a three-dimensional hole structure endowed the APN aerogels with good insulation, flame-retardant properties, and compression resilience. Even under a compression strain of 50%, the aerogel maintained its resilience over 500 cycles. The incorporation of polypyrrole and nickel particles further enhanced the conductivity of the aerogel. Consequently, the final APN aerogel sensor demonstrated high sensitivity (10.78 kPa⁻¹) and thermal stability. In conclusion, the APN aerogels hold significant promise as ultra-broadband microwave absorbers and pressure sensors.