INVESTIGATION OF THE AGGREGATION PHENOMENON OF POLYANILINE IN DILUTE-SOLUTIONS

Aggregation of polyaniline chains in dilute solutions was observed in N-methyl-2-pyrrolidone by light scattering, gel permeation chromatography, and viscosity measurements. The aggregation resulted in a negative second virial coefficient in light scattering measurements and concave reduced viscosity curves. The driving force for aggregation is assumed to be a combination of hydrogen bonding between the imine and amine groups and the rigidity of backbone, and the aggregation was modeled to occur via side-on packing of wormlike chains. Polyelectrolyte-like viscosity behavior was also observed when a small amount of salt was added and the electrostatic interaction in polyelectrolyte polymer based on the Odijk theory was used to explain the role of the salt.