화학공학소재연구정보센터
Journal of Materials Science, Vol.53, No.13, 9635-9649, 2018
Microwave absorption by watermelon-like microspheres composed of gamma-Fe2O3, microporous silica and polypyrrole
Uniform gamma-Fe2O3/microporous SiO2/polypyrrole (Fe/m-SiO2/PPy) microspheres (MSs) with "watermelon-like" structures were successfully fabricated using cetyltrimethylammonium bromide (CTAB) as a pore-directing agent. In the "watermelon-like" microspheres, gamma-Fe2O3 nanoparticles represented the seeds, m-SiO2 the pulp, and PPy the rind. Through synergistic harnessing of the magnetic loss properties of gamma-Fe2O3 and the dielectric loss properties of the m-SiO2/PPy core/shell structure, the Fe/m-SiO2/PPy MSs displayed outstanding excellent electromagnetic wave absorption (EMWA) properties. The maximum reflection loss (RLmax) of Fe/m-SiO2/PPy was - 51.24 dB (7.44 GHz) with a thickness of 4.0 mm, with an effective absorption bandwidth (EAB) (RL < - 10 dB) of 4.16 GHz at a loading of 14.2 wt% in a paraffin wax matrix. These results conclusively demonstrate that Fe/m-SiO2/PPy MSs-containing composites are very efficient EMWA materials and that porous core/shell/shell structures offer a promising approach for the rational design of lightweight high-performance EMW absorbers.