CONDUCTIVITY RELAXATION OF POLYANILINE

Measurements on polyaniline using dielectric analysis (DEA, -50-degree s-C to 240-degrees-C, 0,4 Hz to 10(5) Hz), differential scanning calor imetry (DSC, 30-degrees-C to 240-degrees-C) and infrared spectroscopy (IR) after heat treatment from 25-degrees-C to 300-degrees-C are carri ed out. After conversion of DEA results to complex electric modulus, t he conductivity relaxation time distribution can be obtained, which re mains unchanged for temperatures below 160-degrees-C and becomes narro wer in the temperature range from 180-degrees-C to 240-degrees-C due t o the occurrence of crosslinking reactions, as is confirmed by the exo thermic behavior above 160-degrees-C and by the decrease of the relati ve intensity of quinoid absorption with respect to that of the aromati c ring. The crosslinking reaction causes a decrease in dc conductivity , a narrowing in conductivity relaxation time distribution and an incr ease in activation energies for conductivity and conductivity relaxati on.