Three-color electrochromism of an aramid film containing polyaniline and poly(o -phenylenediamine)

An aramid, poly(p-phenylene terephthalamide) (PPTA), was prepared as a mechanically stable film. When aniline was electro-oxidi/ed using the PPTA-filmed electrode, the film captured polyaniline (PANI). For the obtained composite film. PPTA strongly suppressed the oxidative deterioration of PANI, and fully oxidized PANI (pernigraniline form) was stable without deterioration. The film showed three-color electrochromism: pale yellow (−0.4 V). green (+0.4 V), and violet (+1.2 V). Different color change was also obtained with a PANI-PoPD-PPTA composite film: vermilion (−0.4 V), green (+0.4 V), and violet (+1.2 V).