THE MOLECULAR-WEIGHT OF SULFONIC-ACID RING-SUBSTITUTED POLYANILINE BY LASER-LIGHT SCATTERING

The weight average molecular weight (M(w))BAR of the sodium salt of as-synthesized sulfonic acid ring-substituted polyaniline (SPAN) was determined by light scattering measurements. The water solution of SPAN was first reduced with hydrazine to render the solution almost colorless. The M(w)BAR of the reduced SPAN sodium salt was found to be 11 000. It is concluded that the lower limit of the number of ring-nitrogen units per polymer chain is 39 in the as-synthesized SPAN.