Spectroelectrochemical investigation of electrodeposited polypyrrole complexes with sulfonated polyelectrolytes

Abstract

Films of polypyrrole(PPy)-polyelectrolyte(PE) complexes have high potential as active material in bio-sensing and biomedical applications due to high hydrophilicity and biocompatibility, as well as, as an electroactive polymer matrix in electrode materials for rechargeable lithium batteries and supercapacitors. Comparative study is presented on the influence of PE structure on the properties of PPy-PE complexes. PPy films were prepared by pyrrole electrochemical polymerization in cyclic voltammetry, potentio- and galvanostatic regimes in aqueous solutions of acid or salt forms of sulfonated polyelectrolytes (PEs) with different flexibility of the polymer backbone. Electrochemical polymerization of pyrrole in these conditions results in obtaining high-quality polymer films efficiently rechargeable in aqueous and nonaqueous media. The films obtained were characterized by cyclic voltammetry, UV-Vis-NIR spectroelectrochemistry in aqueous and nonaqueous media, as well as, by Raman spectroelectrochemistry in aqueous medium. Gaussian deconvolution of the Raman spectra in the range of 850–1150 cm−1 allowed one to trace peculiarities of polaron-bipolaron transitions depending on the PE structure. It was shown that the films of PPy complexes with the salt forms of rigid-chain PEs had redox numbers comparable to those of the complexes with the flexible-chain PEs, but they were more stable during CV cycling in nonaqueous medium.