Aggergation of polyaniline and its derivatives in n-methylpyrrolidinone solution

Summary form only given. Distinctive interchain aggregation behavior is observed in the NMP solutions of polyaniline (PAn) and its derivatives, poly-o-toluidine (POT) and poly-o-anisidine (PAs). When the PAn concentration (c) ranges from 0.025wt% to 2wt% corresponding ln/spl eta//sub r//c is not linear to c. When c is below 0.5wt%, PAn (POT or PAs) displays quasi-polyelectrolyte characteristics. The amount of LiCl in the solution has great effect on the aggregation behavior of PAn, addition of 0.1M LiCl into the solution can completely eliminate this kind of aggregation and ln/spl eta//sub r//c resumes to be linear to c as for common polymers. The aggregation depends greatly on molecular weight (MW) and experimental temperature. Higher MW causes more seriolis aggregation than lower one, and the aggregation is weakened at elevated temperature. The critical aggregation concentration (Cc) for POT or PAs is higher than that for PAn clue to the weaker interchain interaction for POT or PAs than that for PAn. Defect state and stiffness of the corresponding backbones are also responsible for the aggregation of PAn and its derivatives in their NMP solutions.