Microwave absorption properties of gamma-Fe2O3/(SiO2)(x) -SO3H/polypyrrole core/shell/shell microspheres

摘要

Highly regulated gamma-Fe2O3/(SiO2)(x) -SO3H/polypyrrole (FS (x) HP) composite core/shell/shell microspheres are successfully prepared through a SiO2 sol-gel process and an in situ polymerization of pyrrole monomers. gamma-Fe2O3 functions as the "core," whereas SiO2 and polypyrrole (PPy) act as the "shells" of the composite. In contrast to many previously reported FS2H-P and PPy-based composites, the FSx HP composites display substantially improved microwave absorption properties, which can reach nearly - 43.1 dB (15.1 GHz) with a broader effective absorption bandwidth (RL - 10 dB) of 6.1 GHz. The excellent microwave-absorbing properties of the FSx HP composites are closely associated with the layer of SiO2 shells and can be attributed to the proper impedance matching and synergistic interaction of the special core/shell/shell structures, dielectric loss (SiO2 and PPy layers) and magnetic loss (gamma-Fe2O3). These results show that the core/shell/shell structure may be an efficient and promising way to improve microwave absorption properties.