Structural, electronic, and morphological changes in poly(phenylenesulfidephenyleneamine) upon electrochemical doping

Structural and electronic transitions in poly(phenylenesulfide phenyleneami ne) (PPSA) upon electrochemical doping have been investigated. The results indicate that polarons are the predominant charge defects at low doping lev els, yielding an electronically and mechanically stable material, The elect rochemical doping at high potentials induces a transition of the polarons t o a bipolaron state. Due to the heterogeneous nature of the polymer chain a nd different oxidation potentials associated with aniline and phenylene sul fide units, the formation of polaron and bipolaron is distinguished as two separated steps. The dopant perchlorate ion exists in the polymer matrix, n ot only as charge neutralizer but also as a ligand that is simultaneously C oulombically bound to the positively charged S or N sites on one polymer ch ain and hydrogen bonded to the N-H group on the neighboring chain. The form ation of such perchlorate anion centered Coulombic/hydrogen-bonded complexe s has a major impact on the electrochemical activity and the morphology of the doped polymer. Also due to stabilization of the dopant ions, the doped polymer can be retained in a stable and desirable oxidation state.