Anisotropic electromagnetic wave absorption performance of Polyimide/multi-walled carbon nanotubes composite aerogels with aligned slit-like channels structure

Polyimide/carboxyl functionalized multi-walled carbon nanotubes (PI/MWCNTs-COOH) composite aerogels with aligned slit-like channels structure were synthesized through unidirectional freezing, freeze-drying and thermal imidization process in sequence. The composite aerogels with high porosity and low density exhibited highly aligned slit-like channels structure, which further imparted anisotropic electrical conductivity, electro-magnetic wave absorption, and compression properties to the aerogels. PI/MWCNTs-COOH-16phr composite aerogel showed the minimum reflection loss (RLmin) of -52 dB at 12.8 GHz and effective absorption bandwidth of 6.7 GHz (10.6 similar to 17.3 GHz) with a thickness of only 2.5 mm in the perpendicular direction to the aligned slit-like channels, while its RLmin was only-11 dB at 15.9 GHz in the orientation direction of slit-like channels. The composite aerogel had prominent thermal stability, with T-5% in nitrogen up to 564 degrees C. The high temperature resistant and lightweight polyimide-based highly efficient EMW absorbing structural material manufactured by this research had great potential for aerospace applications.

Automated summary

Polyimide/carboxyl functionalized multi-walled carbon nanotubes composite aerogels with aligned slit-like channels structure were successfully synthesized, showing anisotropic electrical conductivity, electromagnetic wave absorption, and compression properties. One composite aerogel exhibited minimal reflection loss at 12.8 GHz and wide effective absorption bandwidth, demonstrating great potential for aerospace applications.