Fibrillar Growth in Polyaniline

Abstract Large, colorless aggregates are observed during the induction period of a chemical oxidative polymerization of aniline in dilute aqueous acids using an ammonium peroxydisulfate oxidant. Observed for the first time by static and dynamic light‐scattering (LS) measurements, these aggregates are believed to be anilinium–peroxydisulfate ion clusters whose shape (spherical or rodlike) plays an important role in the overall morphology of the emeraldine salt formed (granular or fibrillar). The role of these aggregates in influencing the morphology of polyaniline is further evaluated under a variety of reaction conditions, for example, varying ionic strength, concentration, temperature, nitrogen substitution, and so forth.