Conducting polymer composites are of great interest from the practical point of view,
because their electrical properties can be tailored by properly choosing the components and
their relative concentration. In this paper we report the unusual aspects of the behaviour of
dc conductivity of a polystyrene (PS) matrix doped with carbon particles (C) and, in another
case, carbon particles encapsulated (Cenc) by a thin layer of another polymer. We study
samples with different concentrations of carbon and try to relate the observed behaviour with …