Enhanced microwave absorption in Ni/polyaniline nanocomposites by dual dielectric relaxations

Ni/polyaniline (PANi) nanocomposites were prepared by chemical polymerization, and electromagnetic characteristics were then studied at 2-18 GHz. The permittivity of the Ni/PANi nanocomposite presents dual dielectric relaxations with increasing content of PANi to over 15.6 wt %, which is ascribed to a cooperative consequence of the core/shell interfaces and the dielectric PANi shells. Additionally, the permeability presents a strong natural resonance around 2-8 GHz, which is dominant among microwave magnetic loss. The proper matching of the permittivity and the permeability contributes to enhanced microwave absorption. (c) 2008 American Institute of Physics.