THE ELECTROCHROMIC RESPONSE OF POLYANILINE AND ITS COPOLYMERIC SYSTEMS

Conducting polyaniline (PANI) and its copolymer films of poly(aniline- co-o-toluidine) (PAOT) and poly(aniline-co-o-anisidine) (PAOA) have be en electrochemically synthesized. The optical and structural propertie s of PANI, PAOT and PAOA have been studied using UV-visible absorption and X-ray diffraction techniques. The X-ray diffraction study reveals a crystalline structure for PANI whereas it shows an amorphous struct ure for PAOT and PAOA conducting copolymer films. Moreover, the switch ing lifetime, applied voltage, cycle lifetime in the glass/ITO/conduct ing polymer/HCl/ITO/glass configuration of PANI, PAOA and PAOT have be en experimentally investigated. Further, the current transient for col oration and discoloration has been analysed in order to understand the charge transport in conducting polymer and copolymeric systems. It ha s been shown that PAOA shows better electrochromic response (143ms) th an PANI and PAOT systems. It is believed that the presence of the -OCH 3 group in the PAOA copolymer facilitates the torsional angle between aniline and methoxy aniline. In addition, the effect of HCl acid molar ity on the switching response of PAOA conducting copolymer films has b een studied. (C) 1997 Elsevier Science S.A.