Liquid Plasma Iodine Doping of Electrochemically Synthesized Polypyrrole to Enhance the Electromagnetic Absorption

摘要

Abstract Polypyrrole (PPy) was electrochemically synthesized and doped with plasma glow discharges on a liquid solution with iodine to enhance the electromagnetic absorption and the transference of electrical charges in the polymer. The results indicated that the electromagnetic absorption in the 200–350 nm wavelength interval increased submerging the polymers in the iodine solution; however, when plasma glow discharges were applied, the absorption increased, and additional peaks appeared in the 600–800 nm interval. The electrical conductivity had also an increase of approximately one magnitude order in average with the plasma doping, from 0.0086 to 0.05 S/cm at 50 °C. The activation energy of electromagnetic absorption as a function of wavelength and conductivity as a function of temperature was calculated finding positive and negative values, which suggest different mechanisms of electromagnetic absorption for non-, semi- and conducting polymers promoted by the liquid plasma iodine doping. This kind of plasma doping can also be used to enhance other surface properties in different materials.