Superior microwave absorbing properties of O, S, N codoped carbon planar helixes via carbonization of polypyrrole spiral nanowires

Lightweight, and broad and strong absorption are still a huge challenge for electromagnetic (EM) wave absorbers. Here, we propose a facile oxidative polymerization-carbonization strategy to synthesize O, S, N codoped carbon planar helixes for superior EM wave absorbers. The spiral cetyltrimethylammounium bromide crystallites act as a template for the in-situ oxidative polymerization of pyrroles into ordered PPy spiral nanowires. Sintering temperature ( T s ) was used to adjust the defects, heteroatoms, graphitization degree, and properties of the carbonized products. With T s varying from 400 °C to 800 °C, internal stress and heteroatom (N, O, S) content decreased, causing the decreased defect/dipole polarization and increased graphitization degree and conductivity loss. As a result, one broad high-frequency absorption band was exhibited by carbon planar helixes produced at 400 °C− 500 °C, two broad absorption bands were exhibited by those formed at 600 °C, and three absorption bands were exhibited by those formed at 700 °C − 800 °C. The carbon planar helix formed at 700 °C exhibited broader bandwidth (4.96 GHz), thinner sample thickness (1.4 mm), and stronger absorption (−35.44 dB) than those of other absorbers. The superior properties are attributed to a combination of dipole/defect polarization, interface polarization, conductivity loss, multiple scattering, and multiple LC-resonances generated from the unique planar helical structure, defects, heteroatoms, and local electric network. • A facile oxidative polymerization-carbonization strategy for carbon planar helixes. • Modulation of the defects, heteroatoms, graphitization degree. • Investigating electromagnetic wave absorption capabilities. • Revealing the enhancement mechanism of the microwave absorption.