Phase-separated, conducting composites from polyaniline and benzobisthiazole rigid-rod polymer

As an alternative method for processing polyaniline (PANI) from its conduct ing (protonated) state, vacuum casting of PANI from a methanesulfonic acid (MSA) solution provided films with electrical conductivity values of about 130-150 S/cm. In addition, we similarly prepared blended films of PANI.MSA and poly(p-phenylene benzobisthiazole) (PBZT). This process eliminated the need for a subsequent protonation step and had the additional advantage tha t the conjugated PBZT may provide alternative conducting pathways. Conducti vity values of the composite films ranged from 100 pS/cm to 124 S/cm, and t he films displayed critical concentration behavior with a PANI threshold co ncentration of 2.75% and a critical exponent of 4. Transmission electron mi crographs displayed phase-separated regions with PANI forming a continuous network at high concentrations. Thermogravimetric analysis results demonstr ated the thermal and thermooxidative stability advantage of the blends due to the PBZT component. (C) 2001 John Wiley & Sons, Inc.