Radiative and electrical properties of granular materials: application to mixtures of insulating and conducting polymers

The study of the radiative and electrical properties of granular materials coated with polypyrrole (PPy) a conducting polymer, shows the influence of the processing conditions concerning the nature of the substrate and the deposition parameters. Binary mixtures with varying compositions of mono and bidisperse particles, coated with or without PPy (which are conductive and insulating, respectively) present electrical percolation thresholds which can also be found when the radiative aspect is considered. The principal component analysis carried out on the spectral values allows us to corroborate the experimental factors and to distinguish the mixtures according to their compositions.