Frequency independent AC electrical conductivity and dielectric properties of polyaniline-based conductive thermosetting composite

Electrical impedance characteristics of polyaniline (PANI)-dodecylbenzenesulfonic acid (DBSA)/divinylbenzene (DVB) composite were evaluated as a function of PANI content in the frequency range of 10²-10⁸ Hz. Polymer composites were prepared by a one-step thermal process where doping of the PANI and curing of the polymer matrix DVB have occurred simultaneously in the presence of a strong protonic acid, i.e. DBSA. The alternating current (AC) conductivity value with respect to frequency of the PANI-DBSA/DVB composite shows a direct current (DC) plateau up to an extensive frequency range. Almost metal-like behavior is obtained with such highly conductive plastic material. In all frequency regions, composites with higher PANI concentration showed a frequency independent behavior, while in the case of neat composites without PANI, a frequency dependent behavior is observed. A plot of the real part of complex impedance vs. frequency and a plot of AC conductivity of the composites indicate that the high electrical conductivity in high PANI concentration composites is because of the direct contacts between filler PANI particles. In this work, AC conductivity behavior and dielectric properties of very highly conductive thermoset composites are presented, and it is shown that conductivity is frequency independent for a very high frequency range (up to 10⁸ Hz).