Porous VGCF@polyaniline nanohybrids with manipulated porous structures for effective microwave absorption

摘要

Micro-nano structure regulation of polyaniline and impedance-matching design of its composites are two crucial but challenging works in microwave absorption. In this study, an in situ sacrificial templates polymerization is applied to regulate the porous structures of polyaniline decorated on vapor-grown carbon fiber (VGCF). By manipulating porous polyaniline structures, heterogeneous interfaces, polarization centers, and geometric structures are introduced into porous VGCF@ polyaniline nanohybrids. Porous VGCF @polyaniline demonstrated robust microwave absorption ability with a minimum reflection loss of- 55.9 dB at 10.3 GHz with a filler loading of 18 wt% and a thinner thickness of 1.33 mm. The investigation of the novel porous polyaniline structures and composition relationship suggest that the microwave absorption ability of porous VGCF@polyaniline is originated from the optimal impedance-matching ratio, enhanced dielectric loss, and synergistic effect, which is enhanced by conductive loss and interfacial polarization. A universal approach was proposed to address the critical issue of hybridizing porous VGCF@polyaniline with flexible polyurethane sponge as practical electromagnetic absorption structures. The hybrids exhibited interesting dual absorption properties with minimum reflection loss of - 28.8 and - 35.5 dB at frequencies of 8.5 and 8.7 GHz, respectively. This study provides a new approach for designing lightweight and practical microwave absorbers.