Preparation and characterization of chiral polyaniline/barium hexaferrite composite with enhanced microwave absorbing properties

摘要

The composite of chiral polyaniline (PANI)/barium hexaferrite (BF) was synthesized by in situ polymerization using L-camphorsulfonic acid as chiral dopant. The structural features of the obtained composites were characterized by FTIR, XRD and FESEM techniques. Open circuit potential was measured in D-/L-ala-nine electrolyte in order to identify the chirality of the composite. Microwave absorbing properties were investigated by measuring complex permittivity and complex permeability in the frequency range of 26.5-40 GHz. As a result, chiral PANI/BF composite exhibited excellent microwave absorbing properties with the minimum reflection loss of -30.5 dB at 33.25 GHz with a thickness of only 0.9 mm, and the absorption bandwidth of the reflection loss below -10 dB could reach 12.8 GHz (from 26.5 to 39.3 GHz), which almost covered the whole Ka band (26.5-40 GHz). The enhanced microwave absorbing properties were attributed to the helical structural characteristic and the good impedance matching between BF particles and chiral PANI.