Microwave properties of conductive polymers

Conductive polymers are a new class of microwave absorbing materials which show a number of advantages over traditional granular material. Polypyrrole, Polyaniline, and Polyalkylthiophenes can be applied in specific fields where the conductive inclusion is directly integrated in the matrix or on the substrate (honeycomb, textile) during systhesis, instead of being mechanically dispersed as in the case of extrinsic conductive materials. This method can be used to produce materials with specific properties, whose performances are equivalent to those of magnetic materials but with lower surface mass. The properties of these materials can be easily modified by chemical means and by tailoring the structural properties. We show that dielectric properties strongly depend on the microstructure of conductive polymer. For that purpose, the influence of the molecular weight, density of defects, size of the alkyl chain on the substituted monomer and nature of counter anion have been explored. A theoretical models using physicochemical properties of polymer have been developed in order to calculate the frequency dependence of (ε′, ε″) with for a chain of Polyaniline.