Electrically Conductive Polymer nanocomposites have attracted lots of attention in the last years, especially for their sensitivities to external solicitations, like temperature or pressure variation. This work concerns the modelling of toluene diffusion behaviour in poly(ethylene-co-ethyl acrylate) (EEA)-carbon nanoparticles (CNP) CPC. One of the main objective of our work was to control and model the physical mechanisms involved in this type of material during sorption and desorption phases in the presence of solvent vapour. Two approaches was explore, thin layer to study quick electrical response and thick layer to look after swelling effect induces by toluene. The thick layer mass measurement was compare with our diffusion model.