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 study the ion exchange mechanism of polyaniline (PANI) and sulfonated polyaniline (SPAN). Anions are predominantly used as charge compensating species in the first oxidation step of PANI at high pH (>2). Protons plus anions are expelled during the second oxidation step. In the case of SPAN, protons are expelled during the first and second oxidation step. In a nonaqueous electrolyte anions are exchanged during both oxidation steps of PANI, while expulsion of cations seems to be the dominant flux during SPAN oxidation. The charge density of SPAN is found to be ca. 44 Ah/kg. The electrochromic properties of SPAN are similar to those of PANI.