Facile fabrication of SBA-15/polypyrrole composites with long-rod shape for enhanced electromagnetic wave absorption

Functionalized SBA-15 has attracted considerable interest owing to its highly ordered mesoporous structure, well thermal stability and great potential applications. Meanwhile, as was demonstrated, polypyrrole (PPy) with good electrical conductivity is also a very popular absorber-related candidate. Herein, long-rod shape SBA-15/PPy-X composites were successfully synthesized via a simple hydrothermal treatment by combining in situ chemical oxidative polymerization method. The SBA-15/PPy-X composites exhibited effective absorption band (RL  <  −10 dB) and electromagnetic wave absorption capacities in comparison with the pristine SBA-15 sample, which were pertinent to the properties of strong dielectric loss and better impedance matching, implying enhanced dielectric properties by modifying with suitable amount of PPy species. The minimum reflection loss (RL) of SBA-15/PPy-0.5 composites reached −44.7 dB with a very low filler loading (15 wt%), corresponding to the thickness of 3.5 mm at 8.9 GHz. Besides, the effective absorption bandwidth was up to 6.1 GHz (11.1–17.2 GHz) and 3.8 GHz (7.4–11.2 GHz) with the thickness of 2.5 mm and 3.5 mm, respectively, which can cover most of the Ku-band (12–18 GHz) and X-band (8–12 GHz). The results indicated that the newly designed silica-based SBA-15/PPy-X composites can be promising EMW absorbers with an excellent performance at a target frequency (typical radar channels).