Infrared study of electrochemically prepared homo and mixed polymer films of azulene

Abstract

Electrochemically formed homo-polyazulene and mixed polyazulene-polypyrrole films have been studied by infrared spectroscopy. Infrared spectra are consisten with a polymerization mechanism that involves loss of hydrogen atoms and produces an amorphous polymer structure. The spectral differences between the oxidized (conducting) and reduced (non-conducting) forms of polyazulene show the presence of a polarization interaction in the oxidized polymer, even though the structure of both forms is similar. The i.r. bands of anions are present only for the oxidized form of the polymer, a result that indicates the existence of cationic charge centres on the polymer backbone. The counter anions have no detectable effect on the polymer structure and only a small effect on certain vibrational bands of the oxidized form. The electrochemical preparation of a mixed polyazulene-polypyrrole phase is discussed and the mixed phase is found by i.r. spectroscopy to be a random copolymer. A bilayer polymer structure consisting of polyazulene and polypyrrole was also prepared and the i.r. spectra of this polymer structure did not indicate any interfacial interactions.