Abstract
The rapid advancement of artificial intelligence demands multifunctional materials integrating electromagnetic wave absorption (EWA) and thermal management capabilities for next-generation electronics. Herein, a facile and scalable Joule-heating carbonization strategy is proposed to regulate the amorphous-to-graphitic phase ratio in polymer nanotubes, achieving a precise modulation of EWA performance. The nitrogen species transformation during carbonization induced enhanced polarization relaxation, defect generation, and dipole polarization, synergistically facilitating charge transfer. Polypyrrole-based polymer nanotubes treated at 1000 o C (PNT-1000) exhibited a maximum effective absorption bandwidth of 3.46 GHz and a minimum reflection loss of −45.1 dB. Moreover, PNT-1000@polydimethylsiloxane (PDMS) demonstrated a thermal conductivity of 2.26 W/(mK), while PNT-2000@PDMS achieved a significantly higher thermal conductivity of 4.20 W/(mK). This work systematically elucidated the interaction between amorphous and graphitic phases in controlling both EWA and thermal conductivity, which is helpful for applying carbon-based materials in these advanced fields.