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

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-alanine 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. Crown Copyright (C) 2014 Published by Elsevier B. V. All rights reserved.