Dopamine-derived cavities/Fe 3 O 4 nanoparticles-encapsulated carbonaceous composites with self-generated three-dimensional network structure as an excellent microwave absorber

• Published in: RSC advances 2019-01, Vol.9 (2), p.766-780
• Main Authors: Guo, Lin, Gao, Sheng-Shuai, An, Qing-Da, Xiao, Zuo-Yi, Zhai, Shang-Ru, Yang, Dong-Jiang, Cui, Li
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c8ra08851a

Dopamine-derived cavities/Fe O nanoparticles-encapsulated carbonaceous composites with self-generating three-dimensional (3D) network structure were successfully fabricated by a facile synthetic method, in which sodium alginate provided carbon matrix pores and excellent microwave absorption performance was established. The hollow cavities derived from the core-shell-like CaCO @polydopamine were creatively introduced into the 3D absorber to significantly improve the absorption performance. The sample calcined at 700 °C exhibited the most outstanding microwave absorption performance, with minimal reflection loss up to -50.80 dB at 17.52 GHz with a rare thickness of only 1.5 mm when filler loading was 35% in paraffin matrix. The effective absorption bandwidth of reflection loss < -10 dB reached 3.52 GHz from 14.48 GHz to 18 GHz, corresponding to the same thickness of 1.5 mm. In contrast, the sample without hollow dopamine-derived cavities showed poor performance due to poor impedance matching, and this highlights the role of hollow cavities brought into the 3D structure, which led to a difference in interfacial polarization, multiple reflections and scattering. The novel dopamine-derived cavities/Fe O nanoparticles-encapsulated carbonaceous composites with 3D network structure can be regarded as a promising candidate for application as a microwave absorber with strong absorption.