Control of Polyaniline Particle Shapes

Needle-like poly(aniline p-toluenesulfonic acid) complex aggregates were synthesized by oxidative polymerization, yielding conductivities of up to 3 S cm -1 and maximum aspect ratios of 26. Rod-like aggregates as precursors to be developed into needle-like aggregates were obtained with 1 to 2 h APS addition time at 15 °C. Flake-like polyanilines were prepared at -2 or +20 °C with 1.9 to 2.5 h of APS addition time, giving aspect ratios of 2 to 10. Plate-like polyaniline aggregates emerged when xylene was added, and an optimum xylene concentration was 15 vol.-%, giving 1.3 S cm -1 conductivity. The polyanilines were characterized by optical microscopy, SEM and UV-vis/NIR spectroscopy.