Self-assembly of poly(o-methoxyaniline) hollow microspheres

Hollow microspheres of poly(o-methoxyaniline) (POMA) were prepared in a solution of p-toluenesulfonic acid (p-TSA) using ammonium persulfate (APS) as oxidant. The morphology of the final polymers was characterized by scanning electron microscopy and transmission electron microscopy techniques. The molecular structure and electrical properties of the products were investigated using a range of spectroscopic methods. The mechanism of nanostructure formation was studied in the light of the chemical nature of the starting monomer and other synthesis conditions, such as the reaction temperature and time and the concentrations of the oxidant and of the dopant molecule. It was established that the mechanism of microsphere formation is based on polymer growth on preformed micelles, which could be seen in freeze-fracture experiments. The presence of p-TSA led to microspheres with a very regular size distribution. The CH₃O-group on the aniline side chain also increased the electrocatalytic activity of nanostructured POMA films cast on a glassy carbon electrode for ascorbic acid (AA) oxidation, in comparison with polyaniline nanotubes.