Incorporation of Nano Particles of Cobalt Ferrite into Conjugated Polymer Matrix for EMI Shielding Applications

Abstract

Intrinsic conducting polymer along with conjugated bonds has been attracting much attention as advanced materials. Especially Polyaniline is one of most attractive conducting polymer because of its high conductivity & stability in air. The research work deals with conducting ferromagnetic nanocomposite prepared by the insitu emulsion polymerization of aniline monomer with cobalt ferrite in different monomer to ferrite weight ratio at 0°C in aqueous solution of dodecyl benzene sulfonic acid(DBSA). The structures of the polymer composites were characterized by X-Ray Diffraction, Fourier Transform- Infra Red, Ultraviolet– visible (UV–Vis) absorption behaviors, thermal stability by Thermogravimetric Analysis, particle size was measured through XRD, and the microwave absorption properties in 12.4-18GHz are carried out with Network analyzer. The resulting composite possesses the conductivity of 0.2-0.4S/cm and saturation magnetization of 22emu/g respectively. These conducting polymer–ferrite nanocomposites are particularly used as electromagnetic wave absorbers and EMI shielding materials, it is very important to explain the variation of permeability and permittivity in the measured frequency ranges. The effects of the weight fraction of PANI-cobalt ferrite composite on the frequency dispersion characteristics of the complex permittivity and the electromagnetic interference shielding effectiveness of conducting polyaniline PANI- cobalt ferrite composites has been studied in the range of 12.4 to 18 GHz. It was observed that shielding effectiveness of the PANIcobalt ferrite nanocomposites increases with the increase in the concentration of cobalt ferrite in conducting polymer composites. The shielding effectiveness of PANI-cobalt ferrite nanocomposite has been found to be 22.3 dB between 12.4-18 GHz for the nanocomposite of 1:3 volume ratio.