Electric relaxation in chemically synthesized polyaniline: study using electric modulus formalism

A method of dielectric spectroscopy was used to determine the electric properties of chemically synthesized polyaniline (PANI) with special emphasis on the influence of acid and water doping levels on the polymer properties. The dependence of the dielectric loss factor (tan δ) on the temperature (in the range from − 100 to + 100°C) and the frequencies of the ac voltage (F = 0.1–30 000 Hz; amplitude of the voltage 1 V) were measured. They were subsequently transformed into the temperature and frequency dependences of a complex electric modulus, M*. Tan δ(F, T) and M(F, T)) presentations were both used in the analysis of the electric properties of PANI samples to compare their informative possibilities. At least two modes of the polymer response to varying temperature and frequency were resolved. Each mode corresponds to a certain area in an electric map of the system (log F versus 1/T plane) with their positions displaced towards higher frequencies and lower temperature with increases of both acid and water concentration in PANI. This effect is interpreted in terms of a unified mechanism of interaction of water and acid molecules with polymer backbone.