Toward strong X-band-electromagnetic-wave-absorbing materials: polyimide/carbon nanotube composite aerogel with radial needle-like porous structure

Abstract

Due to high conductivity, lightweight, good corrosion resistance, and designable structure, polymer/carbon aerogels have attracted considerable attention and have become a candidate for a new generation of electromagnetic interference shielding materials. However, caused by the disordered honeycomb micropore, most polymer/carbon aerogels show relatively low absorption shielding effectiveness/total shielding effectiveness (SE_A/SE_T) at present. This feature will restrict the application of polymer/carbon aerogels in some specific areas, such as stealth aircraft and reconnaissance planes. In this work, a regular microporous structure was designed to address the above issues through radial freeze-drying methods. The fabricated polyimide/carbon nanotube aerogels with radial needle-like porous structure show excellent thermal stability, compressive mechanical properties, and electromagnetic interference shielding performance (∼53.1 dB with a thickness of 2 mm in the axial direction). The SE_A/SE_T value of the polyimide/carbon nanotube aerogels is as high as 94.5%.