This work presents the synthesis by plasma and the characterization of polypyrrole-polyaniline-iodine copolymer thin films. The objective was to study the conditions to randomly copolymerize different and noncombinable monomers to create new copolymers with enhanced selective properties. The study was focused on the influence of the monomer mass ratio r on the structure of the copolymers. The monomer ratio r is important since it represents the contribution of each monomer to the structure and to the properties of the copolymer. The mainstream techniques used to characterize the plasma polymers were infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The electric conductivity was studied as a function of the relative humidity. The results indicated that the copolymers with iodine have better conductive properties at lower relative humidity and that the copolymers without iodine are more stable at moderately high temperatures.