COMPARATIVE-STUDY OF THE ION-EXCHANGE AND ELECTROCHEMICAL PROPERTIES OF SULFONATED POLYANILINE (SPAN) AND POLYANILINE (PANI)

Probe Beam Deflection and Quartz Crystal MiCrobalance were used to stu dy the ion exchange mechanism of polyaniline (PANI) and sulfonated pol yaniline (SPAN). Anions are predominantly used as charge compensating species in the first oxidation step of PANI at high pH (>2). Protons p lus anions are expelled during the second oxidation step. In the case of SPAN, protons are expelled during the first and second oxidation st ep. In a nonaqueous electrolyte anions are exchanged during both oxida tion steps of PANI, while expulsion of cations seems to be the dominan t flux during SPAN oxidation. The charge density of SPAN is found to b e ca. 44 Ah/kg. The electrochromic properties of SPAN are similar to t hose of PANI.