Facile synthesis of polyaniline 'sunflowers' with arrays of oriented nanorods

Polyaniline (PANI) “sunflowers” made of arrays of oriented nanorods were synthesized by chemical oxidative polymerization of aniline in the presence of cetyltrimethylammonium bromide (CTAB) and suitable concentration of HNO 3 at about 0 °C (ice bath). The reaction conditions, such as the concentration of reagents and reaction temperature were systematically investigated and controlled on the preparation of PANI “sunflowers”. The results also suggest that HNO 3 probably plays a key role in forming PANI “sunflowers”. A possible forming mechanism of the PANI nanostructures is offered.